We have this conversation like once every couple of months and the answer is the same: The Legend of Dragoon.
With some major graphics updating and better voice acting, it could work as an AAA title for Sony. The battle system is already modern enough for even people afraid of RPGs to play. Also, the story is pretty light for newbies to RPGs. If they want, they can even make the whole battle system realtime and allow the additions to be like combos. The possibilities are endless and Sony is wasting that to out source most of their successful titles. That's going to hurt them in the long run but whatever.

Motorstorm

spider man

I was gonna say Jak and Daxter but apparently there's some new release I didn't see. However out of those I'd pick medieval

The Getaway........ "you sl*g"

I'd really love to see PlayStation Allstars get another chance. I think it was a really good idea and it was a fun game to play, there just wasn't enough to do and I feel like in a sequel they could expand on it and make it into a really great game.

Is wipeout dead?

Gateaway is a maybe. Many want it but the estimated cost is a bit to great at this time.
Wipeout you can bet you shall see on PS4, mark my words.

Starhawk
Legend of the Dragoons
Jak

Ape Escape. The one for PS1 was probably the 2nd best 3D platformer of all-time.