A VII remake would be simple enough to do. Obviously recreate the visuals so everything looks and feels current, which is easy (looooool) enough, but the hard parts would be recreating the battle system so it feels fresher. Something like an amped up variation of the system in XIII, but without the paradigm shifting, maybe materia sets that you'd premake beforehand. Limits stay the same, but look flashier and do more damage. Seriously, the basic game itself needs nothing done, just update the visuals and exploration, like a custom camera or the nostalgia view like metal gear solid 3. The original system isn't even crusty enough to not hold up in a current rpg today, but the addition of the materia set changes would be cool in my opinion.