I'd love to see Ace Combat 2 (ps1) and the Ace Combat games on PS2 get remade for the current console gen. those were great games.
Dino Crisis ! I loved this game series so much... (Only 1-2, not 3 ..) esspecially Dino Crisis 2.. a new spin off or remake would awesome !
Super mario RPG and Dark Messiah of Might and Magic would top my list. story of DMMM wasn't all that great, but its ability to kick enemies and really make use of traps puts it above even today's top games, imo.
SMT Online: Imagine. Roaming an apocalyptic wasteland with sword in one hand and gun in the other, and your trusty mythical companions at your side, joining up with other players to defend against angels attempting armageddon and demons rampaging near the few human settlements left. It had technical issues but a new version could solve those.
Something with unique/uncommon gameplay: Azure Dreams [PS1] (action rpg + tame monster + dungeon crawler + a little bit city management) Car Battler Joe [GBA] (car battle + car customize + action rpg + adventure) Steambot Chronicles [PS2] (customize able mech + action rpg + rythm music game + multiple ending) Suikoden 2 [PS1] (Great story + cooking mini games + fisihng mini games + castle upgrading + many character + a lot of secret things to search + strategy + rpg) Metropolismania 2 [PS2] (City building & management with third person view, building your house and interaction with npc) Fun singleplayer/multiplayer: Team Buddies [PS1]