I guess the physics do differ. That could be kind of great but kind of a problem too, sometimes... I like SMB1's physics and inability to backtrack, they give the gameplay a heavy leaning on inertia. You can't always make a long or high jump without some speed and you can't brake and turn around from a run, so you have to decide how to deal with what's coming at you quickly and chew on your mistakes. Cool levels could be made to capitalize on that. But any level possible in SMB1 physics would probably be much less dangerous in SMB3 and World's... Can you force or recommend a mode?
I think the deal breaker here, for me, is that it's on Wii U. We've had easy-to-use level editors for Mario games for years. I've used 'em. I probably have Reggie! and Lunar Magic. You know how often I'm at home and have access to those and think, "I'm gonna make and play some Mario ROM hacks!"? Very rarely. I think this one is a way obvious match for the 3DS instead. You're on a bus, or waiting to have your teeth drilled or something--THAT'S when you'll want some Mario levels that you'll only play once.
I don't think Nintendo is doomed or stupid or anything, but, this seems to be the theme for why I don't have or play a whole lot of 3DS or Wii U games. They're on the opposite machine from what would have made them the best they could have been. Mario Maker and Game & Wario should just trade places with the Zelda remakes and Luigi's Mansion. Kid Icarus Uprising too, probably. I mean sure it's episodic enough to play in short bursts but it comes with a stand, so it clearly wants you to hold still while it gives you carpal tunnel
