I really want this game to be great on Vita, but I'm worried about the controls. IMO, the Vita doesn't offer a solid solution to games that use the clickable sticks and L2/R2 buttons on a controller.
Sure, the touch screen can take decent place of two of them (not ideal but serviceable), but the rear touch pad is just horrible IMO. For me its placement and size means that I must hold the Vita awkwardly and uncomfortably in order to not accidentally tap the pad, something I still do on (not so rare) occasion.
Maybe it's just me, but I think the Vita was pretty poorly designed when it comes to replacing the clickable sticks and L2/R2. Too bad the Vita Slim didn't solve this problem. I would've upgraded to it in a heartbeat if they came up with a better control solution.
I really want to support Borderlands 2 on Vita because I think it's a great game, but also because I want more games like this (less indie, more "AAA type" games), so I will buy it, but I'd be lying if I said I wasn't worried about how it will play.