I think as long as he continues to find new, original and funny ways to pursue the whole divided room/audience trope, it will remain a nice signature part of his shows.
For instance in Content Provider, it provides a neat jumping off point for some of the best jokes. Personally I wasn't as impressed as I expected by that show, though mainly because each previous successive one managed to raise the bar every time - hence topping Carpet Remnant World would have been a tall order.
Not only does dividing the room set up some great jokes, it sets up the overall tone of the show. It allows the character of Stewart Lee to maintain the pretence he is disdainful of his audience, without actually punching down at them.
It also sets up some neat ways for him to make fun of his typical hardcore fan, playing with the notion that we like to think we are really smart consumers of clever comedy.
If he used it the same way in each show, I agree that would become potentially tiresome. However so far I see it more of a thematic device, which maintains a though line in-joke for regulars whilst also serving various other purposes, such as those I've referenced.
