Agreed. If it's wall-to-wall cheese, ask the DM to make an attempt to improve, or take a break.
If he wants to improve as a DM, but is struggling, it probably makes sense to have him run a small, isolated adventure in a totally separate campaign with different characters, as others have suggested. That way, even if it's not that fun for everybody else, at least it's not screwing up your campaign as a whole, and he gets some DM'ing experience and maybe learns how to run a game that is more fun for everybody. That's if he's actually willing to make a good faith effort to be a little more receptive to player innovation.
But, if he isn't interested in making that good faith effort, he shouldn't be DM'ing.