Assuming I do not have to care about market realities, I would make a JRPG with massive scale and cutting edge visuals. Battle system would be Grandia II (because Square Enix sure isn't doing anything with it!) based and could have couch co-op where character control be split how ever P1 and P2 wanted. Be able to have tons of side quests and new game + and hidden super dungeons.
Story would be darker with more nuanced characters and seeing various factions and threads woven together as you play across different parties. The musical score would have to be full orchestra with plenty of epic movements in the score. Character design would be bold and distinctive with some classic JRPG clothing choices.
So, I would be so happy and my company would probably go brankrupt.
