Should i sell my 3DS and get more games and accessories for my VITA?
I don't play my 3DS often and the only game i have on that appeals to me is maro kart 7, i have a vita and i have Fifa 13,Mortal Kombat(Got free on PS+) and Assassin's Creed and there are more vita games i'd like to play such as COD and Uncharted.
What should i do?
It really depends, is there nothing else coming out you'd like to play for 3DS? I'm sure tons more games worth playing will come out on 3DS but if you don't want it and there's not really any games you're looking into there's no reason not to sell it. Personally I spend hours on my vita daily with all these sales and great games coming out this season the new year is only going to get better.
Whatever you feel like doing is up to you. In thinking about the situation, though... are there absolutely no games on the horizon that you have your eye on? Did you only get the 3DS for Mario Kart 7 or are you attracted to upcoming titles such as Animal Crossing: New Leaf, Luigi's Mansion: Dark Moon, or maybe a more recent Mario escapade like Paper Mario: Sticker Star?
If none of these or other known games out there in the 3DS lineup seem likely to sell you on continuing your pursuit with the handheld, then by all means use it for something more useful like credit toward the Vita games and accessories.
I've been thinking about this as well, and personally I've decided to keep mine. Sure I absolutely hate nintendo's marketing for games on the thing (i.e. "New" Super Mario Bros. 2 for those that remember), but there's going to be Smash Bros, Monster Hunter, and Pokemon Mystery Dungeon being released for it, the former two being released in March for NA. Nothing seems appealing to me at the moment besides those games, but it's also early in it's life span so I'm going to wait.
I must say though, I've been enjoying my Vita much, much more than my 3DS (got my 3DS in February and got the AC Vita when it was released). If nintendo first-party titles have lost nearly all their appeal, I would go ahead and sell the 3DS.
But with games like RE: Revelations, Kid Icarus Uprising, DoA: Dimensions. Monster Hunter 3 Ultimate, Fire Emblem, Luigi's Mansion, Kingdom Hearts: DDD amongst others, I really think you should make sure first there's nothing that interests you before doing something hasty~.
Well, I would say no, as others have said, due to the vast amount of games available and upcoming.
But like they all said, it's based on your interests.
If you happen to own a Wii U, Monster Hunter 3 Ultimate is coming out on the Wii U and the 3DS, and will feature a Cross-Save sort of thing (you can play on the Wii U, and then continue on the 3DS. Much like PS3/Vita Cross-Save on games like MLB 12 The Show)