Its funny to see this thread because just yesterday I was thinking this same thing! And im sorry if you guys are talking about PVE, but seriously I have not seen a real tank in a level 1-49 PVP match in like 20-30 games. And I know that this is kinda obvious because tanks suck for pvp but I used to see them all the time.
I use to PvP all the time in the 1-49 matches on my PT tank. I usually ran with a dedicated healer and we just went around stomping people. Having multiple CCs from my healer friend, and my Jet Charge/Grapple were just deadly in Huttball with those fire traps.
There is just something very satisfying about being nearly unkillable in PvP ... of course this was quite a while ago, now that everyone has had time to gear up I dont think it will be quite as easy