I personally would love to see a successor to Planescape, or Kotor 2, sadly you don't have any rights to the later.
Any old school isometric RPG should be pretty good and I think there are enough Fans to support such a thing.
The obvious advantages were that you could have as much development time as needed, and a isometric RPG doesn't a ton of funding, so you should have enough time to make a big, polished game and restore your slightly tarnished reputation for making buggy games.