Yes, I have seen a game prototype before, even made a few of my own.
I'm also not jumping to conclusions without reason. You've clearly started the brainstorming phase BEFORE seeing who is interested. The combination of your previous wording and the fact that I've seen your brainstorming doc says to me that you are planning on going ahead with that as the springboard. Maybe you are, maybe you aren't, but that's how it comes across.
The thread should have been oriented to see who is interested in making the game, and have everybody post up what they would be interested in doing with regards to the game itself, not just the asset creation. Then you can pick who you think is qualified to contribute. You said this isn't an ideas thread, but you can't separate the two, because somebody interested in making a game may not be interested if that game is nothing like the kind of game they would want to make.
For instance, I am not a fan of MOBAs. I feel like they are basically an extremely simplified form of RTS where you don't have to worry about base-building and assaulting the enemy because all of that is on autopilot. If I want to play an RPG-like character, I will go and play an RPG that has a legitimate story and character development. If I want to control a character in an RTS environment to directly contribute, I will go and play Battlezone or Nuclear Dawn. To that end, I wouldn't really be all that interested if a MOBA is what comes to pass. This is also why I'm leaving Game Design as a career choice, because I don't want to make something I have no stake in.