Would any game religion pass IRL? No, of course no, no one has the time to develop a religion to that extent. However, with a bit of suspense of disbelief, and can imagine that if there is enough written on the key fundamental questions, then there are answers, "unwritten", on most of the rest.
If there's nothing to work on, however, I cannot suspend disbelief to tell myself that such a religion would give satisfying answers to the fundamental questions of life.
Fun doesn't make "good", in my book. You can have a bunch of nobles actively preaching about how squirrels will end us and about how we must worship the holy badger while wearing pink tutus, and RP a bunch around that and actively spread it. Could be fun. Would be stupid as hell, though, and wouldn't qualify as "good" in my book simply because it is fun.
Does a lot of theology text result in a lot of tl;dr? Yes, of course. But then again, I'd bet most SA players never really read the few SA texts there are either, and almost all of them never contributed to developping RP. So what's your point, if the end result is the same in both cases? At least when there is established theology, those who did bother can lecture others on the proper way of doing things. Hell, at least there is a determined proper way of doing things, for those who cared enough to look it up. When in the Cult, I had on many occasions people come ask questions to me about this or that, obviously not having read the wiki. It was a great opportunity to link various bits of lore with current events, and therefore publish new lore or documents. Indeed, a lot of texts you can see on the cult's wiki didn't just come out of my ass on day 1, it was the result of interaction with others.
I 100% disagree that intentionally leaving more blanks than text makes a religion better. It's certainly a key to success to not have any arbitrary rules as RL religions have as even the smallest rule will turn away some people, but that just makes for a !@#$ty (even if successful) religion. A good religion should feel like it could have been a real western religion in the days.
