Hey Slashie.
I'm Ray, a longtime poster on rgrd.
It looks like forums like this one have pretty much killed rgrd dead, so I started looking around to see where the community had gone.
Now, in answer to some questions:
I consider it rude for an application to force itself fullscreen. It's assuming I'm doing nothing else, watching nothing else, or using my computer for nothing else. That's far too presumptuous. Games, especially, are somewhat "social," and I may have a web browser or usenet client for a dedicated game website or game forum, text editor for writing reviews or taking notes, chat client or skype session to talk to other players in realtime, etc. at the same time as the game. These kinds of things are part of the same "play session" to me, and if the game makes it impossible to do them, they become major features missing from the play experience.
So, if I want to maximize an application, I will maximize the application. If I want to change its aspect ratio, I will grab the corner and pull and if it doesn't figure out how to use the new aspect ratio I'll be annoyed. Resigned, because few games "get" that - but still annoyed.
Second, the "game session" is not even usually the only thing going on, on my computers - nor is it the only thing I care about while it's going on. If I'm at work being the compile-farm, render-farm, or server-farm babysitter (which I have to take a turn at once a month) I damn well better have a terminal screen up to catch "WALL" messages from whichever cluster I'm responsible for, and I damn well better act promptly on those messages. Although on a good night nothing happens, the entire purpose of that particular task is to respond promptly if and when something (usually a router or drive failure) does happen. The penalty for as much as a two-minute delay would involve losing my privileges to play games at all during those work shifts. This is one of the reasons I play turn-based games; I can instantly pay attention to something else and come back an hour later when the something else is resolved.
Third, whatever ideas you may have had about screen sizes and aspect ratios, if you're dealing with people who have to read documents a lot, double them. A bunch of us have portrait-oriented monitors, which is a regular monitor turned ninety degrees, because it fits the A4 page size that a lot of the documents we have to read come in. And that's a lot more significant than, say, the difference between 16x9, 16x10, and 4:3 ratios.