Why would you want MGS5 on Vita? How about its own stand alone installment like Portable Ops+/Peace Walker.
Leave "Metal Gear Solid" mainline series on consoles and spinoffs/enhanced ports/remakes on Portables.
because that could actually save the Vita like MGS4 saved the PS3 early on
Get Your Portable ID!Lord of Ratchet and Clank
Duke of Playstation Plus
Warden of Platformers