I love both, still as you said they aren't as good as Mario64 for many reasons.
What SMG needed is more freedom, in M64 when you enter a level you don't have a forced objective, you can go for the star you prefer. Also, and more important, in M64 you aren't forced to do a anything in the way the designers have tought, almost every platform and action in the game can be perfomed in the way you like it, I can't think of other 3D games giving you this kind of freedom. This video explains better than words.
As for future 3D marios, I'd like Nintendo to bring back some focus on exploration on WiiU. On 3DS, I'm ok with a more immediate type of game (like 3D land should be).