Exactly. There isn't any wiggle room on what is crap and what isn't if you have experience, that would have been the whole point.
For monitors I don't know the exact ratio because I'm bad at "the mathz" in my old age, but the larger the screen, the further back the control panel has to be. So if that's the case then there's no point in having a exceedingly large monitor. There are some situations where it makes sense, like lightgun games and sometimes sim games, but that's because you stand/sit much further back.
It's the same thing with tvs btw, which is why it boggles my mind that home theatres have caught on. A large display is for a large room, where the seats are far back and thus you need to make the image look the same as it would in a smaller room with a smaller tv. Unless you are one of those freaks that sits in the front row (seek help), the image your eye sees sitting somewhere in the middle of a movie house is just about the same size as your tv at home.
I actually had problems with a modest 27 inch crt in my original mame cab.... it just wore my eyes out looking around. With the new lcd in it's more like 23-24 inches in 4:3, which I feel is about right.