I enjoyed the first one when it came out in 2006, and played it to completion. But despite several attempts to replay it, I just can't muster myself to play more than the first world. It just doesn't have "it". Meanwhile, I still play both Super Mario Bros 3 and World at least once a year and I have for literally decades. At least the Wii version has difficulty.
This one doesn't look to add anything. Same engine, a Tanooki suit, and some coin powers. What's really unnerving is that it uses the same old songs for each level type. They are not even that good of songs besides the castle theme, and the old Mario games always had new songs each game (and they were better than in this game). This just looks like a cheap cash-in sequel that seem too prevalent these days. I know the "real" Super Mario Bros. 2 did the same thing in Japan in 1986, but at least it's hard as hell. I don't have a 3DS at the moment, but if I get one I will only pick this game up on the cheap.
Of the resurgence of 2D platformers over the past 6 years, Rayman Origins is the best followed by Donkey Kong Country Returns. I'm glad NSMB sparked off the genre again, but it's not one of the greatest and this one doesn't look to be either.