Having done my time in the 70’s, when, as no doubt in today’s military, I signed an enlistment contract and, of course, completed it.
For the guys in today, if DADT is negated, I would think that their contract is null and void: you arbitrarily changed the condition of their service. And, were it me, I’d be gone, since there are things in life that I just don’t have to put up with.
So, from my point of view, go ahead and revoke DADT, but them renegotiate each and every enlistment, including officers, but in particular the enlisted, who live under much worse conditions than their “betters”.
I suspect that you’ll have to rif the former, as you’ll have very few of the latter left.
There are quite a few military on FR that have said they’ll not reenlist. I don’t blame them. There are some very cogent reasons not to serve with homosexuals, moral and unity being two of them.