Yes, NDA sounds kind of silly.
Maybe I should, but I don't necessarily see GM guidance in character creation as a red flag. Sometimes participation in thought out worlds requires anchoring the character some events, persons, or whatnot through background. Among a group of gamer-strangers, wouldn't the lack of GM involvement imply the lowest common denominator: an average American high-fantasy? If anything (any kind of character) goes, PCs don't really matter as there is no cohesive setting beyond the steeplechase? That society around the PCs, if there is one, will not react their actions beyond necessary plot-points: quests, clues and straight-forward rewards? So the game is about success as specified by rules?
I know one novelist GM. I haven't played in his campaigns, but those that have, have enjoyed them. Are novelists are better or worse GMs than other people? Are they micromanagers with their worlds (more often than not)?
I think that James S. A. Corey's excellent "The Expanse" series is based on Ty Franck's MMORPG (then table-top RPG) setting. IIRC Steven Erikson's Malazan series is based on his fantasy world (and he uses GURPS). I would have loved to play in their campaigns - although I don't much care for Malazan series.