Searching for Game Designer (2.5D, Gamepad, Portable)

I'm searching for someone with a strong independent and entrepreneurial spirit who enjoys analyzing and reasoning about game mechanics and to design the core play loop of a game. You should also be good at explaining in written communication how things are supposed to work and why psychologically that'll make the game addictive/pleasant/enjoyable.

Ideally, you will already have released some unpolished games by yourself and now you're looking to team up to upgrade your graphics/sound/marketing.

I have lots of experience with UE4 and Unity and I have access to programmers, 3D designers, artists, musicians. I also have existing relationships with console and portable manufacturers and access to development kits. Once finished, we can re-use my battle-proven marketing and launch team. And lastly, I have experience with IP protection, trademark law, and game-related action figures. For example, I have the equipment to produce custom amiibo in my office.

The only thing I really lack is someone with a good game idea and the ability to explain how things need to work to be enjoyable. I can do the technicalities of measuring in-game events, organizing play-testers, etc. But I need someone who knows what to measure.

My industry contacts are looking for a 2D or 2.5D indie game that is both casual and suitable for testosterone-driven male teenagers. The game mechanics should lead themselves well to being played on a portable device (small screen) with gamepad. I was explicitly asked NOT to produce yet another free to play & micropayments title, so the game will need to be novel/creative enough for people to spend $9.99 to purchase it upfront.

I'm asking here on IndieHackers because ideally, I am looking for someone to partner up more long-term, should this project work out OK. From what I've heard, the mean time to success for video games is 3-4 releases. Payment would be either a low-ish monthly salary or post-expense revenue share for the resulting games, or a mixture of both.