I'd like to see Tag from Mod Nation Racers, he could be in a kart which obviously looks different but would play no different than having legs. His moves could be based off MNR weapons, spin, slap, there is plenty to work with.
if anything tag should just be an alt for sackboy. Both characters are represented in the others game through dlc and the companies seem to get along. I like tag but i dont see that happening. maybe a mnr level cross over though
Two of the most requested 1st party characters within reason. Syphon Filter has been on PS1, PS2 and PSP and Bend are often rumoured to be working on a Vita installment. Legend of Dragoon nails an RPG rep which will shut a lot of people up.
wander and ico are way more requested then gabe logan.
Maybe you missed "within reason". We know Team Ico don't want their "art" sullied. So that's them out. And then more or less every other fan request is third party or ridiculously obscure.