I did not like CRZ. The very idea is idiotic and insulting, a giant slap in the face from Blizzard to their customers. "Yes, we realize the zones are empty, so here's a way to make them feel populated without addressing any of the real problems related to underpopulated or dying realms."
Thanks to CRZ, I now compete with more players for fewer rare spawns, and also have similar issues with gathering, and with quest mobs that don't respawn fast enough. (I didn't see a single Black Lotus in the months I played after CRZ launched.) There's increased opportunity for pvp ganking. (Yes, I know that ganking shouldn't happen on PvE realms. However, there are ways to encourage or trick potential victims to flag themselves. Or the would-be griefers can just slaughter quest-givers and vendors.) I can meet players from other realms, but I can't invite them into my guild, trade with them, or even be confident that I'll see them again. Hell, I can't even reliably carry on conversations with the people I see, since traveling through zones can cause us to phase apart, never to see each other again.
CRZ fixes nothing, and encourages the transitory, non-social feeling of modern World of Warcraft. Sure, there are lots of other players, but it's not like how you treat them actually matters.
The one thing I suppose CRZ may succed at: fooling brand new players that the realm they've selected isn't an empty wasteland, even though it is.