The bottom line is that NSMB2 is far better than NSMB DS and that is all that counts for me.

They shouldve changed the map to a single big world map and called the game New Super Mario World and I guarantee you this same game would sit at 85+ Metascore right now.

Can you tell me what evolution has happened in the 2D platformer genre in these past 6 years then? I wasn't aware the genre has developed even further, is it: Story? Art style? Puzzles? Bite-sized levels? User-created levels?

Do you mean the Japanese Mario 2 (aka lost levels) or the Doki Doki Mario 2? 

And yeah, I agree with you.  There were plenty of Mario alternatives for people looking for variations on the Mario formula.  I guess Nintendo knows that Mario has a particular brand of loyalty amongst fans.  If Super Princess Peach had starred Mario, I think it would have done much better in sales.  It was a pretty solid game but, withouth Mario on the box, many people didn't even give it a second look. 

One of the few series that almost always gets it right is Metroid.  I guess Grand Theft Auto and Castlevania do a good job of this, too (for the most part).  As for the last part of your post--I openly admit that we have no idea what we want.  When companies start listening to us and changing things to fit our demands, that's when things start getting generic and bland.  I think NSMB2 is barely outside of that window but I hope Nintendo goes their own way with the next game.  Make the game they want to make instead of making the game they think we want them to make.  It usually works out better for everybody when they don't follow some check list of demands.

The sad thing is that I think you're 100% correct.

One "proof" of what I'm saying (change is cyclical) is that if you look at the changes people want, most of the times they are throwbacks: world map, spin jump, yoshi, etc...

I do love Metroid too - the 2D ones -I suck at console FPSs, the DS was allright but just because of the finger stylus  - but for example, I didn't liked fusion that much. Then Zero Mission came with gameplay more "primitive" than even Super Metroid and bang - struck me down like lightining.

Also, I just really dislike when people say NSMB was not innovative. Just the ability to kick walls (in 2D) is more definitive than 47 world maps and 345 yoshis + lots of new enemies and stage dynamics (known as gimmicks) than ever. I've still to play NSMB2, but if they just continue this trend it's fine. More than fine.

Nintendo is just playing safe with the visuals. In a way it's understandable. Mario as a brand is more uniform now. His 3D model for example is now the same in all the games as it is in your pajamas and in my cereals. Toad, Peach, bowser, etc... too. Then, if you see sales, usually changing too much means less sales, and nintendo knows 3DS is in a very delicate state right now to risk something as huge as mario. Wii U too is in a pretty delicate state.

Reviewers would rather have 3D Mario than 2D Mario. Consumers would rather have 2D Mario than 3D Mario. There's a huge disconnect between the establishment press and the ordinary consumer. NSMB2 got panned for not being another SM3DL, nevermind that it's an awesome 2D platformer.

Basically, the press want Nintendo to make games specifically for them, not for their general consumer base who absolutely ADORES 2D Mario. I think the establishment press' hatred toward NSMBWii pretty much confirms this.

I've noticed this in other things, too.  Tablets, for example.

People wanted home computers, and then computers small enough to take with them.  Then, it reached a point where people had smart phones that could do most of what a computer coud do in the palm or their hands.  Now, people are leaning towards tablets (which just look like bigger cell phones to me) and wanting add on keyboard for their tablets.  It's like they want what they already had.  I think that by the time it's over, we'll be right back to having giant Batman computers in our homes....and people will want them to be smaller.

Same goes for portable consoles.  We want them small but when they get too small, we want them bigger.  When they get too big, we want them smaller.

Link?

True. But I chose Modern Warfare 3 as an example for a reason

Hahahaha :P I also find it weird that Fifa and Madden games can constantly get 90's, but Mario games don't. Don't get me wrong I'm a big Fifa fan, but really if anything the 2D Mario games evolve better with every iteration (level designs, co-op, jump mechanics) than Fifa and Madden. That's why I think it's a bit of a double standard.