I think it's silly to say he has nothing left to prove in AAA and equally silly to say he's not hurting the ML team right now. He is definitely hurting us. We're just good enough to overcome it right now.
Holliday barely had a cup of coffee in AAA. He was only ok at the end of last year in AAA (.796 OPS) and had good stats when everyone on the team had over a 1.000 OPS against the lame White Sox team early this year. He also barely had a cup of coffee at 2B. Most importantly, he looks broken right now.
There's every reason to put him into a position where he can decompress and find his legs again. While he's at it, he can figure out how not to drop his hands so he can compete at the top of the zone, and he can get more comfortable at 2b.
I love the kid and believe that he'll be as great as they say, but I definitely believe he was rushed in relation to how Elias has really made sure the other guys are more ready before promoting them. Nobody else got the Holliday treatment, and I don't think they should.
I would demote him and give Norby a shot, effective tomorrow.