I've heard of pushing the envelope when it comes to game sequels, but this goes way too far.
First of all, it has nothing to do with strategy. I found that turn-by-turn attack system with "action commands" very fun. It made a unique balance between the mindless button mashing of most action games and the somewhat boring action select of strategy games. This game is pretty much a make-over of Super Mario Bros. (which we already got from The New Super Mario Bros.).
Second of all, only Mario can move up and down and that is only when he is in 3D mode, otherwise the game is almost completely two-dimensional.
Finally, it really lacked some of the bosses that made the first two great. Any gamer above five years old would rather face a mysterious ice king than a magician in a robot designed by a four-year-old.
So here I say, if you want to rent this game, by all means go ahead. If you want to play anything remotely like the first two games, I'm afraid you will have to look elsewhere.