The end game is strong....still lots to do. There has been a afew changes over the years to the lower levels as well, making replayability higher for leveling alts as well.
Depending on the group style (Exp, quest, named hunting)...different tanks are preferred. Raid wise...there is a place/role for all tanks. Main tank wise seems to show a preference for SKs, Guardians, and Zerkers to a lesser extent lately.