I liked the night time auto-run levels, but there's only like two in the entire game.
Otherwise, Mega Mushroom is useless.
Mini Mushroom is in its useless pre-NSMBU state.
Raccoon tail already got wrung for nostalgia juice (much better) in SM3DL.
The level design is intern-tier. Really good interns, but clearly not experts at the top of their game.
Limited 2-player co-op, regression from NSMBW.
No Yoshi, regression from NSMBW.
No World Map.
Coins gimmick went nowhere.
Same worlds, same music, same assets like all NSMB games.
Put it all together and you have something better than the DS game, but not by a massive amount.