You mean you didn't play the other 5 (but Re:Coded doesn't count). But there's that memo function that summarizes each game's story when you see a certain cutscene and a character from past games appear.
I've never been an early adopter of consoles, then I buy 3DS on its release AND Vita on its release.
I've never experienced a console early life before, and it is no good at all.
You are right again when you say that Mario Kart Wii is better than Mario Kart 7 (in my opinion). But MK7 worth a try. The online play of MK7 is fantastic.
You should try some eShop games too, I really recommend Pushmo and Mutant Mudds. There is also VVVVVVV but this game is too hard for me.