It shouldn't come as a surprise that the game underperformed relative to some early expectations. No one saw the huge backlash/controversy coming. I for one loved the first game yet couldn't bring myself to finish the 2nd, and really fucking hated it, more so after skimming through let's plays.

But I wouldn't rule out that the HBO series + a new marketing campaign may give the games a healthy sales boost and push them beyond the current trajectory. The Witcher 3 did get a serious boost from the Netflix series iirc.

The first half the game is is amazing.  I just didn't like the 2nd half at all.  Felt like a lame attempt to make the game 2x longer than it actually was.  I always compared it to RE2...  scenario B was always optional.  TLoU 2 should have used a scenario option and not forced both stories at once.

The absolute majority of scenarios, maps and assets of Abby's journey are original, so I strongly disagree with your idea it was just an attempt to make the game bigger (I also disagree with RE2, but for other reasons). 

The point of the second part of the game is to show any story has two sides. The third part of the game wouldn't work nearly as well if we haven't see Abby and Lev journey and, of course, how to create connection with both. I frankly just love Lev and hope he comes back later in the series, but anyway.

Gameplay wise I like Ellie's slightly better because I feel she's more focused on stealth, while Abby is more brutal remember me a bit of Joel. Overall I think both maps are equally well designed with a fair share of challenge, with Ellie's journey being more grey, rainy, grimmer and providing a nice view of the desolation in Seattle. Abby's give me a perspective that was still some kind of civilization living there and overall I found her scenarios to being either lighter or outright dark/nocturne, although the differences aren't pronunciated enough as still the same place. 

Narrative-wise is where the most important reason can be found: Ellie journey is about her disintegration and how he was growing more heartless and blood seeking. It was a pain to see the character we already love being consumed by the darkness.

Abby story is diametrically the opposite, she meets two kids and vow to help and protect them . Abby's journey is light-hearted, noble even. The effect is to see a character we hate turning into a better person. At the end of the game I was kinda of sympathizing with Abby so I guess it worked lol

The absolute majority of scenarios, maps and assets of Abby's journey are original, so I strongly disagree with your idea it was just an attempt to make the game bigger (I also disagree with RE2, but for other reasons). 

The point of the second part of the game is to show any story has two sides. The third part of the game wouldn't work nearly as well if we haven't see Abby and Lev journey and, of course, how to create connection with both. I frankly just love Lev and hope he comes back later in the series, but anyway.

Gameplay wise I like Ellie's slightly better because I feel she's more focused on stealth, while Abby is more brutal remember me a bit of Joel. Overall I think both maps are equally well designed with a fair share of challenge, with Ellie's journey being more grey, rainy, grimmer and providing a nice view of the desolation in Seattle. Abby's give me a perspective that was still some kind of civilization living there and overall I found her scenarios to being either lighter or outright dark/nocturne, although the differences aren't pronunciated enough as still the same place. 

Narrative-wise is where the most important reason can be found: Ellie journey is about her disintegration and how he was growing more heartless and blood seeking. It was a pain to see the character we already love being consumed by the darkness.

Abby story is diametrically the opposite, she meets two kids and vow to help and protect them . Abby's journey is light-hearted, noble even. The effect is to see a character we hate turning into a better person. At the end of the game I was kinda of sympathizing with Abby so I guess it worked lol

Very well put. I don't see how people hate so much the idea of playing with Abbie and seeing her suffering and redemption, even though they like to play true villains that are purposed on killing whole countries.

Pacing was my reason.  You get to an amazing climax with Ellie..  and have to wait 8 to 10 hours to see the conclusion via Abbie.  Maybe switching back and forth would have been better?  I didn't personally have a problem with Abbie/scenario B...  just how it was paced/designed.  Does that make sense?  I'm not trying to change your mind, just giving my honest opinion.  For instance when I played Abbie I recall rushing just so I could get back to the climax that was build up quite nicely with Ellie.  So pacing was just weird to me.

I don't think switching every know and then would do much good, that would truly ruin pacing and would already spoil to you that you would play as both and also wouldn't let sink the full weight of Ellie actions you made.

In manga one of the stuffs I hate the most is when protagonist major fight is streached for like 4 volumes because they want to synch every minute of his fight with the fight of other people. That totally breaks my pace.

Fair enough, everybody is entitled to their opinion.  I struggled with the hard break in the climax.  I just was put off by it.  I get the idea/concept, I always understand why others liked it, but it wasn't for me.