Try looking through some of the older movie threads, there's still quite a few video links that still work and show it being done, and you don't necessarily need a dedicated tank class for 5 boxing them. A lot of the more popular comps were built around casters, or consisting entirely of them(With the exception of maybe 1 melee class).

If anything you'd be better off not using one in most cases(though it depends on what we'll have available to us when they release Classic). I can't imagine we'll have IWT + CTM again, so we'll probably be back to using a main melee toon we drive from while the others are on follow to drop away from the mob(s) etc.