1. Final Fantasy Tactics Online. FFT engine, but a persistent world where you attach yourself to a faction (Delita's Ivalice, Northern Sky Loyalists, Death Corps, Romanda, Ordalia, Church) and control of the world (per server) is determined by PVP.
2. A superhero beat-em-up using a modified version of the Red Faction: Guerrilla engine. Punch, blast or just run, Juggernaut-style through buildings. Toss cars (which deform and explode), swing lightpoles. Run, jump or fly through a city at least the size of a major sandbox game's. Infamous/Prototype meets Red Faction, I guess, but with a heavy, heavy emphasis on boss/duel battles between two supers of roughly comparable power, roaming the whole city as they blast each other to bits.
3. D&D 4e: Points of Light. Tactics/RPG in the FFT style that D&D 4's rules are so, so beautifully suited to. I'd prefer if it were made by a Japanese studio with experience at the genre, since the recent (as in, since longer than some people here have been alive) D&D games have sucked. The Wild ARMs XF team would be ideal, although I wouldn't mind another installment of THAT, either.
4. An X-Com remake using the RF:G engine, modded to be turn-based. (Possibly you'd have the option of playing it as a tactical shooter ala Rainbow Six? But it has to have at least the option of turn-based play.) Mostly a graphical update to the original X-Com, but with more different win conditions (think Civ's variety of wincons), more modern equipment to start X-Com off, and possibly the option to play as the aliens. (Or save that for the sequel.)
5. Uncharted 3. No suggestions; Naughty Dog obviously know what they're doing.