From what I remember the plusses to Vegas, apart from the cheap flights, is that while the city/Strip itself is expensive, renting a house just outside the city is cheap. The place IS convention capital of the US, so it has a rental infrastructure to support something as small as us. We don't do a ton of touristy stuff, so most of the time for everyone is spent at the house anyway. If it's an option that limits the prices of the flights and house for everyone, who cares what's around it or where it is? Only added expense thing I can think of is car rental, maybe.
I would want to double-check the numbers on Vegas to make sure these claims are accurate though. But the irrational rejection of it out of hand is a little confusing.
Though yes. It would be hot. We were also in Texas in midsummer though, nothing we haven't experienced. The local knowledge angle is about the only angle that holds water to me, if the numbers are correct.
Jim's house is also an option, and I have my passport so Vancouver is also not a bad option but I'd have to check flight prices