The Vita should have allowed access to someting like Micro SD for a start. That would have taken the sour taste out of peoples mouths before they even bought the thing. Also, it should of had PS2 support. That back catalogue alone would have shifted double what it has done IMO. It wouldn't have been hard in this day and age to cram a PS2 in a handheld and run said games of Vita style carts or digital downloads. Imagine buying a handheld and having day one access to things like Kingdom Hearts, MGS, God Of War, Jak And Daxter (this list is more or less endless).
They should bin the Vita off and release one more handheld. Just called it Playstation Portable and have it able to run PS1, PS2, PSP and Vita all under one system.
PREDICTIONS FOR END OF 2015: (Made Jan 1st 2015)
PS4 - 34M - XB1 - 21m - WII U -12M