Master_of_Oldskool said:
Persona 3/4 + Pokémon.
... Wait, shit. That's basically Pokémon Amie, isn't it?
That's also pretty much what the Shin Megami Tensi games that eventually spawned the Persona series are.
OT: Mount and Blade + The Elder Scrolls
In terms of engaging plot I'm not as critical as most are of the recent Elder Scrolls games, though I agree that Morrowind had the most engaging of the series yet, though there are plenty of gems in all games. However, where the Elder Scrolls series has always been lacking is more engaging combat, and modeling it after Mount and Blade's combat would be a good start at least.
Star Wars + Fallout New Vegas:
I've always wanted to see a truly open world Star Wars game, and whatever else they might be, Bethesda have always been good when it comes to building open worlds. More specifically, I'd either like to see the player dropped into a massive Skyrim or bigger sized world with pretty much every environment and species in Star Wars in it, or a transportation system between several planets that had large areas to run around in, whichever would work better. Wandering around, helping/cheating/killing/etc. doing quests, factions to support or ruin, the possibility of becoming a Jedi/Sith/Something in between but making it balanced so that remaining a normal would still be viable. Most importantly, the world would be designed around allowing you to take any role you want, from smuggler, to peacekeeper, to bounty hunter, stone cold killer, and everything in between. It would also help Fallout's karma system to be more of worth, since your Force powers if you became a Force User would be reliant on it.
Both melee and ranged combat would be available, first or third person. The battle system would have an early warning system involved, i.e. you get a red flash a split second before you are attacked and if you block or dodge in the correct direction with timing you stop the attack, otherwise it goes through. This early warning system would have a margin of error based on how good your fighting statistics are, naturally over time as you successfully block attacks, and if you became a Force User how experienced you were in Force Sensing attacks, though it would still be an extremely brief warning to prevent the player from being able to easily block and dodge everything. As for the story, that's where my ideas end.