I think the thread is getting a little flamey, but I'd like to weigh in here because I think this is an important issue.
I'm not in favor of lowering the group limit at all.
I find that most groups I am in are slightly underpowered with five or six people, which can be quite a lot of fun, and then on days where many friends are around we consistently run with nine or ten. When we do have a full group of ten anyone else who logs in to find the group is full will usually, though not invariably, log off and find something else to do. Keeping the most people on the game as much as possible I think is the goal here, and I don't see how lowering the group limit will help in that way.
Is there some aspect of the notion that I'm not clear on?