I believe skill > gear.
Our guild was doing HM TfB in PvP gear, and we were downing the boss way ahead of the hard enrage.
Using a parser, we found DPS who was getting 1300+ on the first boss was golden. If your tanks know what they're doing and your healers do too, it's a fight for anyone above itemized Rakata (most of us were in itemized WH, which is roughly on par).
But, once again, skill > gear. Some players out there can do 1300 on first boss in a mixture of Rakata / Columi, which is perfect for the rest of the operation.
Thanks for the info. Nice to know there are people clearing HM TfB in WH gear. Have you guys cleared 5/5?
My guild has a good mixture of pvp-focus and pve-focus members. So we will like to mix and match and get some pvpers to experience the new content too. Our pve progression group has cleared HM TB 5/5 in augmented campaign gear. The first two bosses should pose no problem. I felt the thrid boss might be a bit of gear check (well we might not be executing the best of strat).
It will be good to know group in WH gear was able to down the third boss. The last two bosses would be more about mechanics and coordinations than gear.