A Pre-Cure Mousou would be so easy to make, they make a damn movie every single year in which every Precure ever appears, they'd just have to write the game like if it was another of those movies.
A Type-Moon Musou would also be amazing, but I wonder what the enemies would be.
For TM they could probably set the game around the counter force summoning in heroes to take care of shit over the ages, and just fight regular ass soldiers.
It would be heavily slanted towards Fate though.