I have to agree with your assessment of Millbrook. It's not the temps that bother me, it's the vis. I've done Millbrook and Hyde's and the visibility at Hyde's was better IMO, even with a couple of classes going off the dive platforms.
I've only been out to Millbrook once, but speaking with a couple of local instructors, the conditions we had (5' or less vis, maybe 10' in a couple of spots) was pretty standard. Hyde's felt more like 10'-15'. The real bummer is that Hyde's isn't deep enough to do an AOW class in, so all of the local shops run them out of Millbrook.
I've heard the case for learning to dive in the those type of conditions, but my buddy and I decided to deal with the drive and hotel and do our AOW at Dutch Springs instead.
Has anyone done AOW out at Millbrook? Did you get anything out of it?