I'd rather play a five hour hightower match where every class is viable than sit through the forty hour long spamfest that is Dustbowl/Goldrush/Hoodoo/Payload in general.
You can't really "wall" hightower, there's no good sentry spots and if you need crowd and sentry control get a
wartime Demo. Every class is viable there, instead of the soldier/demo/heavy/medic of payload. As a heavy/medic person, I see why you like prefer regular payload.
For stock Gullywash they drained the water under the point leaving a cavern instead, which is the one thing I dislike about it now. The water was a neat gimmick and was why it was called Gully
wash. But oh well, its still a great map and they probably did that for balance reasons to help pyro ambushes.