What do you think that "AMAZING big title" for the PS Vita is?

[SxyxS]

there are just 3 ip's possible
GT
GTA(as you mentioned,but if there is a GTA exclusive Deal than it is more obvious for ps4 as system seller)
Final Fantasy(unlikely as ff10hd is coming)

but i think it is something else as this ip's are too big and need a very big budget