I think comparing the Hyatt to the Motel 6 is quite extreme. I have stayed at the GH SF, and I thought it was great. I received very friendly service all around. The only complaint I had was the poor directions I received from the BART station to the hotel. I had to call 3 times because of the directions I was given. But since there are multiple exits at the Powell St BART, one can hardly blame the mix-up.
As far as the windows being covered, there's two things to be considered:
1. Americans don't really care about opening windows. It's a cultural thing. We'd (most of us anyway) would much prefer the heat/ac to the natural air. The one exception is perhaps at a beach destination where you can hear the waves crashing. The only place I ever make use of the outside in my room is in Hawaii because I love to hear the trade winds and such. But in general, most Americans are not windows open people.
2. The hotel was undergoing rennovations. The plastic was likely there so the window wouldn't get broken. It's a temporary thing. I don't think you can hold a temporary situation against the hotel. When I was in the UK this summer, Windsor Castle had construction going on, but I didn't hate the castle any less because part of it had scaffolding on it. It's temporary, and one shouldn't be angry at the hotel over something beyond its control.
Finally, if the staff was rude (especially at Westlake), I have to wonder if it was because of a negative attitude given to them. If I wanted a different room, I'd call down and politely ask if one was available. I wouldn't immediately begin b*tching about a window that wouldn't open. I'd ask if another room was available. If the clerk said they were booked, I'd say thank you and move on.
I know as well as anyone what it's like to be frustrated with Hyatt. They really go above and beyond to make things right when they can.