Don't forget DCA is a hub. The route from Washington to TPA has a lot of government DoD traffic. Right now UA won the city pair with IAD to TPA. But UA also has EWR as a CO old hub. Any time it gets down to UA vs. old CO, with all CO management, you know CO will win out. IAD is losing flights.
I'd be aggressive and fight for West Florida via TPA. The only problem is Southwest.