I don't think the OT's listed are going to be pure OT's, but rather just perform better as them. Most shield/shield or pure/pure comp parties don't function as well due to mitigation and regeneration not being able to stack, but an OT/OT comp in 8.0 seems to only run into the issue of a few mits not stacking, which is already the case with the current tank balance as seen with reprisal. It's too early to tell but I think OT/OT parties will still be able to function unless they lock damage/lb gen around a perfect comp