I think the more important thing is to make it marketable and focus on the best channels to sell it.

I’d love to continue the Kingdoms Of Amalur franchise (if you can call 1 game a franchise). Action/Fantasy RPGs are my cup’a tea. I’d love to make games like these.

If I was actually capable I'd probably make a Grand Strategy game about the late bronze age in the Eastern Mediterranean east to the Indus Valley Civilization of Pakistan (~1600-1100 BC) somewhat in the vein of the Crusader Kings or EU4, but with some elements from the Civilization series.

It wouldn't be popular, but I know I'd personally love it lol

I'd make a spiritual successor to both Beyond Good and Evil and pre-BotW 3D Zelda since those have a very unique gameplay that's now dead and I miss it a lot. I'm actually studying for a game design bachelor's degree, so hopefully one day I'll do it for real! I would also love to make a 3D platformer.

I'd work in a Tales game. The first thing I'd do is hiring the Suikoden 2 writer to get a very compelling story, and I would make the game cel-shaded like Tales of Vesperia, with a traditional world map instead of those sh**tty ugly fields that the latest Tales games have had. Also, I'd hire Go Shiina to compose the soundtrack.

Also, I'd love to make a Paper Mario game.

Not the same thing but....I had plenty of gay sex in Fable and Dragon Age: Origins. My Dwarf in DAO was sooooo gay. Totally unfaithful too. I fucked everybody I could. For some reason though, I only went lesbian in KOTOR and KOTOR 2. I mean, not exclusively, but once in each game. Have you ever played Cho Aniki?

Everytime I think about this subject I get a little depressed because I wanted to be a developer for years. I could just never invest the proper time or find a team. I know beyond a shadow of a doubt I could make/design an incredible AAA killer app given the right team.

I would acquire Square Enix first by buying the necessary shares. Then I'd fire Testuya Nomura. Then I'd fire the entire English localization department and hire all new staff. Then I'd start making a franchise out of Xenogears by remaking the original as the starting title, then I'd do the same for the Chrono franchise.
I'd give everyone at Visceral that worked on Dead Space 1 & 2 a job and have them remake Parasite Eve 1 & 2.

I would just port over games to VR like crazy. A lot of people say normal games don't work in VR. But I say Skyrim proved the opposite. Everything is better in VR!

Good thing I'm not a dev. I would probably lose a ton of money. =P

Since Nintendo showed the 2D-prototype for testing out ideas for BOTW I think that would be great as a small standalone title. Obviously not as a testbed, but completed with story and all.

I myself would concentrate on making a lot of turn-based RPGs and turn-based strategy games. Best if both can be combined actually.