The point you raise about Milloy's familiarity in the system is certainly reason enough to have him start over duds like Hawkins or Scott or whomever else we now have backing up Harrison.
I mean it's not like we are asking Milloy to replace even a decent starter out of this pathetic grouping.
As I said I saw many Bills games and, more importantly to this discussion, have listened to analysis galore on the merits of Milloy as a player for the Bills.
Milloy's play last year wasn't pro bowl calibre but it was far better than average, despite having to cover up Troy Vincent's struggles opposite him. Milloy still struggles in pass coverage mode - and thus was expendable because he is a horrible fit for the Bills proposed cover 2 scheme - but he's not much worse in this department than Harrison is, and it isn't an issue when Harrison is out there for us.
At any rate, give me a still productive vet who is well versed in the Pats complicated secondary anyday over what we now have as options.