I have a gaurdian tank I do HM fp and ops with every now and then, but tbh i feel like its getting more and more dull. Not as much as my healer mind you, but still very repetitive and predictable. Every fight the mechanics are the same, every flashpoint works the same way. You do the Malgus fight once its not going to be different the next time you do it.
I used to have two tanks (pt and the gaurdian) but the powertech is now a pyrotech and I'm working towards full war hero on him. Pvp is a lot more fun than pve. You never know what to expect in a match, and fighting against another thinking player instead of a programmed npc is more challenging (and fun) than simply remembering mechanics that never change.
that's all debatable because technically, wzs are all the same too. each hutt ball match has the same rules, everyone pretty much has the same plan in Civil War, etc. and to be fair, there's a whole lot more FPs than there are wz maps. i, personally, find pvp to be very repetitive, especially considering that obtaining end game pvp gear is a lot more of a grind than obtaining end game pve gear is. at least it feels that way to me.