I've played since mid Vanilla.
Imo, the game has only gotten better, with the exception of a few small things, like the shift from battlegrounds focusing on pvp and the kills to winning/losing as quickly as possible. Also not super happy with current rogues (and they way they look in Warlords) but this is not because of the game changing, but rather rogues not changing--leaving them feeling stale and archaic and having lost diversity due to other classes gaining rogue signature abilities.