I'll have elite privileges anyway with GM (soon to be PM) status.

What the "Breezeway access" tells me is that my Reserve card is going to be connected into DL's system differently than just as a miles depository. DL will know who its Reserve cardholders are and it sounds like that will be attached to tickets (via the SkyMiles number).

This may give some insight to the upgrade priority question-- or at least we know that DL will have the technical capacity to place Reserve/elite cardholders in a different place on the priority list than standard elite (if this is indeed going to happen). Again, just speculation until someone reports on the Reserve welcome kit.