What's wrong with changing the formulas?
People still complain Pokemon not changing formula.
What Nintendo needs to do is to change the formula but not change the formula.

I'm not saying you're wrong, but I'm giving the game the benefit of the doubt.  Really, though... if the game had the same features as TTYD or the original, it wouldn't be as imaginative or fun.  The game's mechanics do have to change over time, otherwise it gets stale.

The game has obviously changed a lot since 2010.  They announced it way too early.  Partners were in the game two years ago, and not having badge points or experience points is a shame...but I'm willing to give it a try.  I just hope there are extras like a Pit of 100 Trails and optional bosses.

Changing the core gameplay = bad. Battle mechanics, continuous overworld, partners.

Changing the content of the game = good. "You start in a house with your mom and then a professor makes you choose a fire water grass starter and then your rival picks the other one then you walk to eight gyms while fighting an evil Team and meeting rival, then the final battle with Team involves a legendary they've captured/harnessed, after which you face the Elite Four and go into the Hall of Fame". - every pokemon game, getting very tired now.

Can people distingush one from the other? I want the content to surprise/excite me, but I still want it to be the same game I enjoyed playing last time.

This.

This also applies to NSMB2. NSMB2 didn't even have new Power-Ups (The Golden powers aren't exactly game-changing), while NSMBU has new features, that's why it's not getting as much flak as NSMB2. Paper Mario games only need new content, partners and story progression to feel fresh and different.

It's as if Nintendo decided to remove jumping from 2D Mario games and instead add a gun.

For real, this sticker thing can be a hit or a miss for me. I think what they should do is add some kind of option for attacking if you run out of stickers. I really need to get the game to find out. I personally think that the concept is good if they have some kind of weaker attack you can use as a base attack.
Partners were fun to have, but they weren't really what made the game. I personally enjoyed the outside world of the game more than anything else. It seems like they kept that formula the same.

They were for me :( Without them, it'll always feel like something's missing.

I reeeeaeaaallly hope I end up enjoying this game. I really did buy a 3DS mainly for this game (what was first shown from it, not what it's become).

I don't trust them after Super Paper Mario.

Did they? Looks like many individual levels on a Mario World-esque world map to me.

I'm referring more to the things like interacting with the environment.  You know how you can hammer in certain objects and it may react to that?  Or fitting into small areas and other stuff like that?   

My my... people really like to complain.

As explained: there's level up. Just not in the traditional way, cause it would make no sense (you would only choose HP as FP and BP have changed a bit)
As explained: there is "FP". As you level up, you gain more space for stickers - which is exactly the same as FP (more "space" for powers)
As explained: there is BP. Stickers function almost like the same as badges. Want to do a Power Bounce? There's a sticker for it. Want a Power Smash, there's one too.And better, this allows flexibility, you're not bound to use the same ability in fights. Plus, there's much more to this system and to different badges than we don't know yet, so there's probably a lot of cool new stickers that give cool new powers, like frog suit, goat...

Partners are good, but they probably chose not to use them because they would have to recycle them, like they did in all games. One who tattles, one that explodes, one that hit enemies from a distance, one that makes mario pass some barrier (invisible walls, electric barriers,thin spaces, in the end it's the same). Let's try to give this system the benefit of doubt and PLUS, there IS a partner. That little Sticker Crown is named Kersti. She probably has some abilities we don't know yet and will be Mario's voice. And there's temporary partners too.

So there's two ways, the game is done nothing you do will change it. Either wait to play it, or skip it. Anything other than that is:

Btw, Mario RPGs for me is about gameplay, obviously, but the writing is always the main aspect. Super Paper Mario was astounding in this category. Bitland is probably one of Mario's funniest sequences ever. No, one of all Videogame's funniest sequences ever.

1. Did anyone ask for such changes? No. The battle system and structure were universially acclaimed by fans and critics. Not one complain was made about them.

2. It's just cool to have your partners and their wide range of abilities. Partners are also about the dialogue and relationship with them. I don't want some lame generic star.

3. There's also the "Let the game bomb by Paper Mario standards and show Nintendo they can't give us their crap experiments as games".