I have a really hard time taking these criticisms seriously. 
@bozinga - I don't understand the whole "Joel suddenly became stupid" argument. Abby liked and was thankful to Joel. They weren't luring him into a trap- It's nothing like the first game with the scavenger in the street. That scavenger was a "bait". Conversely, Abby wasn't baiting Joel. she actually was about to die. So to Joel, there wouldn't be any reason for suspicion. He just saved her life. I don't see 'this person might turn around and kill me' to be a logical forethought. Perhaps he should have been more cautious, but consider this: Had joel been any other person, he wouldn't have been killed. Logically, the only real argument you can make is that it was stupid to say his own name. However, we've seen in almost any movie or literature on survival, going from difficult conditions to comfortable (living in a town that grew to hundreds within 4 years and are all friends) tends to make people let their guard down. You're entitled to think that Joel's stupidity was just a poorly written plot device, but it's definitely up for debate and you're point is not as singularly convincing as you seem to think. 

Furthermore, the whole setup-confrontation-conclusion argument you brought up hinges on you accurately identifying the story elements. You say that the story is all backwards and mixed up and doesn't make sense. But there are hundreds, if not thousands of revenge stories that are written with a similar type of setup.
-In Kill Bill, you have no idea who Bill is and why he killed the bride or why she wants revenge.
-In The Gladiator, Maximus is an actual war hero and is given heirship to Rome by the terminally ill emperor whose son then kills Maximus' whole family in a bid to steal the throne.
-In Hanna, you have no idea why the government comes and tries to kill her father. all you know is hanna goes bonkers and starts killing everyone. 
-In OldBoy, the story starts of with the lead being kidnapped and tortured and we have no idea why until things play out and you find out the main dude is actually a huge PoS.
-Do I even need to bring up Darth Vader in star Wars being Luke's father? Does anyone really need to see Anakin's life story before I can understand why Vader is so insistent on capturing Luke? 

You say that we need to see Abby's story before we see her kill Joel, but do we really? We PLAYED the first game. We know how bad Joel is. For all I care, the first game IS Abby's exposition. 

Joel is a villain- Despite bonding with him, or liking him, or even agreeing with his actions. Joel is a villain.
When Ellie asks how Joel knew about the trap he responds, "I've been on both sides". He's trapped and killed innocent people EVEN BEFORE he ever meets Ellie.  Regardless of making ends meet or surviving, we also see his moral failures towards the end, wherein Joel offers just go back home and Ellie replies,
"if I don't go through with this, then everything we've done.. everyone we've lost...it's all for nothing"
Joel then kills the entire hospital, the resistance, Marlene, and condemns humanity. Joel betrays and dishonors everyone you met in the game, all bc he wants to keep Ellie to himself.

TLOU is great game specifically due to how the narrative induces compassion for Joel's journey.... If you honestly need more exposition to understand Abby's motives at that part of the game, then I'm afraid to say that it's pretty obvious why. You didn't understand the last of us. 

Playing through it myself, I was also surprised that Abby was out for revenge. I wrongly assumed that since she was kind of normal and I had been playing as her, she would be a good guy. What's more interesting is that even now, I can't think of a reason to say Abby was wrong to kill Joel. AFAIK, Abby's story begins 4 years earlier when Joel kills her father. AFAIK, Abby could actually be the hero of her own story, climaxing with her killing the target of her vengeance. If you think about it, Ellie's journey in TLOU2 is Abby's exposition. Abby is just Ellie from the future, if you understand my meaning. The difference being that Abby didn't spare her target and Ellie does. 

The way you described how the story should have been written, we should have played out an entire story of Abby's revenge and then played out Ellie's revenge. Honestly, I can't think of anything more tedious or boring than having to play out the same plot twice.

or maybe you should pursue a career in film. We definitely need another Quentin Tarantino.

I would say that at the hospital he wasn't at his best mental state and he also knew that if anyone was left alive that knew about Ellie she was going to be hunt. And sure after all the kill he done in the past he wouldn't have issue killing a few more.

Anyway even criminals have loved ones and can act kind. And he being able to sympatize and have real care and love eliminates him being a sociopath.

I'm not saying Joel definitely is a sociopath, but I want to correct you on something. Joel at no point sympathizes with Ellie. Ellie made the decision to finish the job and Joel took that from her. That is the opposite of sympathy and empathy. To empathize and sympathize is to feel what someone is feeling. By making the decision for her against her own wishes, he demonstrates a clear lack of empathy. Saying thatvthat Joel acts out of love overlooks the fact that sociopaths do in fact care for things, but the things they possess. When a sociopath is sad that a friend or pet dies, they aren't sad because that person will never experience life again, nor feel for those that are also hurt. They are sad because they lost their possession.

Id even suggest this lack of empathy is further evidenced in the scene where Joel gives bill his partners suicide note. I think that while some might say it was the right thing to do, it can't be ignored that the letter was a devastating blow that didn't necessarily need to be spelled out. 

You are merely projecting your logic into the matter but don't really have anything concrete to back that up. It's not that Joel does cannot trust people, but it is clear he does not let his guard down that easily. Case in point, when Joel meets Henry and Sam. It took them a while before he completely trusted them. For Abby and her friends, it was almost instaneous. Why he did so is everyone's guess.

However, I kinda see what they may have wanted to portray with this current Joel. Joel has or is trying to move on. His house was filled with things that he likes. He seems to be respected by the people in the town judging by all the flowers people left at his home. Seems like he may be trying be a better person. Not just to Ellie but to everyone else. But without having anything solid to bridge us from TLOU1 Joel and the current Joel, it comes out severly lacking in context and just forces people to formulate theories. I enjoy a story that has a continuous flow. These flash backs served nothing but just force context to conveniently support the events that was happening or is about to happen. It's also one of the things that hurts the pacing so bad.

If you are having a hard time taking the crticisms pertaining to Joel's death seriously, a lot of people are way ahead of you as people like me can't take anything in this game's story seriously with how bad it is.

If someone you love was murdered while trying to do something good, I think you would be able to see "your side" of the story.

I have a really hard time taking these criticisms seriously. 
@bozinga - I don't understand the whole "Joel suddenly became stupid" argument. Abby liked and was thankful to Joel. They weren't luring him into a trap- It's nothing like the first game with the scavenger in the street. That scavenger was a "bait". Conversely, Abby wasn't baiting Joel. she actually was about to die. So to Joel, there wouldn't be any reason for suspicion. He just saved her life. I don't see 'this person might turn around and kill me' to be a logical forethought. Perhaps he should have been more cautious, but consider this: Had joel been any other person, he wouldn't have been killed. Logically, the only real argument you can make is that it was stupid to say his own name. However, we've seen in almost any movie or literature on survival, going from difficult conditions to comfortable (living in a town that grew to hundreds within 4 years and are all friends) tends to make people let their guard down. You're entitled to think that Joel's stupidity was just a poorly written plot device, but it's definitely up for debate and you're point is not as singularly convincing as you seem to think. 

Furthermore, the whole setup-confrontation-conclusion argument you brought up hinges on you accurately identifying the story elements. You say that the story is all backwards and mixed up and doesn't make sense. But there are hundreds, if not thousands of revenge stories that are written with a similar type of setup.
-In Kill Bill, you have no idea who Bill is and why he killed the bride or why she wants revenge.
-In The Gladiator, Maximus is an actual war hero and is given heirship to Rome by the terminally ill emperor whose son then kills Maximus' whole family in a bid to steal the throne.
-In Hanna, you have no idea why the government comes and tries to kill her father. all you know is hanna goes bonkers and starts killing everyone. 
-In OldBoy, the story starts of with the lead being kidnapped and tortured and we have no idea why until things play out and you find out the main dude is actually a huge PoS.
-Do I even need to bring up Darth Vader in star Wars being Luke's father? Does anyone really need to see Anakin's life story before I can understand why Vader is so insistent on capturing Luke? 

You say that we need to see Abby's story before we see her kill Joel, but do we really? We PLAYED the first game. We know how bad Joel is. For all I care, the first game IS Abby's exposition. 

Joel is a villain- Despite bonding with him, or liking him, or even agreeing with his actions. Joel is a villain.
When Ellie asks how Joel knew about the trap he responds, "I've been on both sides". He's trapped and killed innocent people EVEN BEFORE he ever meets Ellie.  Regardless of making ends meet or surviving, we also see his moral failures towards the end, wherein Joel offers just go back home and Ellie replies,
"if I don't go through with this, then everything we've done.. everyone we've lost...it's all for nothing"
Joel then kills the entire hospital, the resistance, Marlene, and condemns humanity. Joel betrays and dishonors everyone you met in the game, all bc he wants to keep Ellie to himself.

TLOU is great game specifically due to how the narrative induces compassion for Joel's journey.... If you honestly need more exposition to understand Abby's motives at that part of the game, then I'm afraid to say that it's pretty obvious why. You didn't understand the last of us. 

Playing through it myself, I was also surprised that Abby was out for revenge. I wrongly assumed that since she was kind of normal and I had been playing as her, she would be a good guy. What's more interesting is that even now, I can't think of a reason to say Abby was wrong to kill Joel. AFAIK, Abby's story begins 4 years earlier when Joel kills her father. AFAIK, Abby could actually be the hero of her own story, climaxing with her killing the target of her vengeance. If you think about it, Ellie's journey in TLOU2 is Abby's exposition. Abby is just Ellie from the future, if you understand my meaning. The difference being that Abby didn't spare her target and Ellie does. 

The way you described how the story should have been written, we should have played out an entire story of Abby's revenge and then played out Ellie's revenge. Honestly, I can't think of anything more tedious or boring than having to play out the same plot twice.

Saying I'm projecting with nothing concrete is a very convenient argument that doesn't really say much. I could come up with hundreds of reasons why he softened, perhaps something like you mentioned about how he became like a town figurehead. Maybe his past four years has been exactly the same as meeting abby, but they instead join the town. Perhaps Joel hated himself for betraying Ellie like he says in the scene right before that when talking to Tommy. Sometimes people tend to get reckless when they feel they've fucked something up. I could come up with all kinds of ideas because just like in a lot of literature, you don't always know the ins and outs of causation. Sometimes you are required to use your imagination. Generally when parts are left out, it's because in the end, it really doesn't matter, nor is it entertaining or concise to watch every single events causes and effect. 

The point being, if you can't bring yourself to suspend disbelief, you are doing a purposeful disservice to the narrative. 

Personally, I am happier to have a concise narrative with 20 hours of story that doesn't hold my hand through every characters formative whims. I honestly find that kind of narrative storytelling insulting and childish. 

I haven't finished the game, so my opinion on the execution may change, but currently I think the only problem in this argument is that we have a difference in what we each consider to be good storytelling.