Haha if this skilled game designer was somehow rich enough not to care about a monthly payment, he would be smarter to just make his own crowdfunding campaign.

This, entirely.

As a quest designer, I wouldn't go with any project for a rev share unless:

A). The studio has a track record in delivering at least one game.

B). They already have a good amount of followers.

C). They can make a beautifully designed world where I can tell the story.

Harsh? Probably, but I don't want a project just to be all talk and then disappear without a trace.

I would rather make my own game, then.