As a DCA-based DL flyer, I'm also really interested in seeing what flights will be retained and what flights will drop from the schedule.
I'm guessing most flights to hubs will be kept, but certain other non-hub flights have come in really handy for me. I'm guessing CRJ200 flights would be the first to go.
The positives will probably be a less crowded DCA Terminal B and fewer of the problems described in threads like
DCA Terminal B - Chaos, so it could end up being a net positive for the DL experience at DCA. We'll just have to see what they end up doing.