I think it would be the touch controls i remembered trying the Uncharted Game demo It was really sad how they made some actions like cutting Bed sheets thats covering your path you have to touch the screen and make a slice like flick which dissapointed me. Its an Action game for cries sake not a lego game they probably thought that they forgot psvita has touch controls and they should spread it all over our faces and make things even worse...I would throw my psvita away if they made cutting throats with silent kills by touch the screen and make a freakin circle like its a dance game --- (H)aving (A)nger (T)owards (E)veryone (R)eaching (S)uccess
Depends what they do with the touch controls. I also didn't really think that touch controls made Uncharted a failure. They were unnecessary, overused and gimmicky (i.e. exactly what you don't want from touch screen controls), but since the core game was still classic Uncharted with traditional controls I didn't think it was a deal breaker.
I'd like to see stuff secondary stuff like triggering Eagle Vision moved to the touch screen for example.
Either way, if Ubisoft just wants to recreate a console AC game on the Vita, they shouldn't run into too many problems related to a lack of buttons. AC's controls just aren't terribly complex. --- "If god didn't want us to eat in church, he would have made gluttony a sin." - Homer Simpson