I just dont see Tankers killing at all, sure they have focused accuracy and a shit ton of health, but, why bother? before they nerfed blasters you could still kill a tanker under Aim and Build up, but now.. it just seems to be all about the status effects.
My advice (dont take it too seriously) is to find something that can hold through 1 breakfree (i got held through 8 Strength of Wills by a dominator, but thats another story) and has an uninterruptable heal, and i think you should be fine for both zone, and arena.
I still say go with a scrapper if you want something for melee.
You have a katana/regen right? just max dmg buff from IO sets, get some decent recharge and you will be fine, hell you can get phase shift and MoG now, its like you dont even need a secondary anymore.