Please no Arizona. Granted, I want to see a move to the southern Gulf coast. I keep saying I'll make it down for SP one year. If the Nats go to Arizona, I doubt I'll ever make it.
I've been to spring games in both AZ and FL, and AZ is a far and away better experience. The teams are all clustered around Phoenix. You can stay in one place and see games at a bunch of different complexes without much driving. Florida - the teams are all over the state with hours of driving between facilities. And the weather is much more consistent in Phoenix.