The heat from May-September (and increased humidity August-September) are draining, agreed. And the desert is a one of those things you either learn to appreciate/respect, or not. I love Flag, though. Some of the best running up there, and I think it's gorgeous. Sedona and Scottsdale aren't my cup of tea, but I live here, so I'm not into the touristy stuff.
The upside is that you can bond with other runners here pretty easily, just by braving the heat.
Comments about gun nuts, etc. are silly stereotypes. I consider myself a moderate independent, not into guns, and none of my friends are either. I have family living in the Midwest who call themselves gun nuts and fit the criteria.
Downtown Phx. is getting better. Some really good restaurants now.
RE the airport, done much traveling elsewhere? JFK and LAX are complete zoos. I just spent some time traveling through Wisconsin and the Milwaukee ariport had some of the rudest customer service I've ever experienced. I'm not into stereotyping, but sometimes you need to get outside the typical "tourist bubble" to find out what a place is really like.