Gangbangs are great, but I understand why some people don't like the idea of playing so many men. Personally, I don't mind them being somewhat flat though if it helps get the scene in motion, especially as you can always give them a modicum of individuality through the sex itself.
Maybe one guy is more confident than the others, getting in first, whilst another prefers to hang back or even take care of himself. Perhaps one guy really likes feet whilst another wants to use her hair. Of course, she cam respond to each in turn to and give them a foil to bounce off, building both her character and each of the men a little more.
Naturally, you can do exactly the same kind of thing with a reverse gangbang scene, or a little of both for an orgy. I think some people are intimidated by the idea of multiple characters, assuming it means they'll have to write pages of stuff to do it all, but I don't really think that's the case. There's even some appeal to faceless characters - a gangbang with strangers is a lot of fun.