1. Space world, Metropolis world, Theme Park World, Minus World, Big World, Pipe World, and basically anything that is not a desert, water, or ice level.

2. More surprises. LIke when you discover the Sky world in SMB3.

3. New Suits: Super Raccoon/Tanooki Suit - extra long flying time that can be extended in some way. Drill suit, Giant suit, Rock Suit, etc. etc.

4. Endless Skies: For flying, the skies can be infinite instead of blocked off by an invisible wall. As you fly up, random content could be created like cloud platforms, coins, secret pipes, and eventually you could see the sky fade to black as you enter space. This could be the way you get to space world.

5. Endless Ground: The drill power-up from SMG2 allows you to dig infinitely downwards. And in the same way as endless skies, random content in created that you can explore.

6. Some 3d Levels: just like 3d mario had some 2d content, 2d mario should have some 3d content. Not anything drastic, of course (no star finder puzzles please). I was thinking more along the lines of a Crash Bandicoot style level where you have to run away from the screen (like in the e3 presentation if you saw it).

7. Online where each player has their own screen and can separate from other players. Street Pass can be used to exchange high scores, low times, etc.

While I agree with most of your things, no 3D parts. Ever. The 2D ones Galaxy were horribly slow and not comparable to what a true 2D level is. Things like this would just split the fanbase.

online and level creator.

Are you saying that Mario should copy Little Big Planet? Do I have to cyber slap you? Mario is innovation and does not copy! lol I think It would be a great idea for creative people like me. 

No level builder. Leave that to the experts.

I just want to run and jump instead of placing blocks.

there are people who can design levels better than the experts though and anyway that would just increase replayability.