As a player there, I can definitely say people aren't just waved in. Two of my friends (who are great writers) were both turned away because the mods felt their take on their characters wasn't really close enough to canon. (So, frankly, if there are a lot of OOC characters in the game, it's not because the mods gave them a free ticket in.)

My friends developed these characters over a long period of time and came up with a lot of great ideas for them, but I'll admit that does take them further from canon than most people are used to. Personally, I'm fond of those characters that way but I understand the mods' decision to turn them down.

And yeah - if the RP wasn't engaging and had a crappy player base, there wouldn't be such a demand to get in.