Tanks can certainly play a role in PvP if they are given mechanics to do so. I like the plan from CRB_Clynch for PvP tanking abilities; taunts, tethers, pulls are all good stuff that can genuinely help a PvP team and make a tank desirable. Would like to see some decent group buffs and buff stripping as well. However, need to make sure there is a limit to the bunker builds that can be created so you don't end up with unkillable tanks which do very limited damage and really slow down PvP. IMO Tanks should still deal considerable damage, less than pure dps but not by a wide margin.