I've thought about this a bit. Dungeon is a great resource, and the best buy in RPGs. The thing I like about Polyhedron is the inclusion of the minigames. So, what if Dungeon went back to being all adventures, and the minigames were put out in a quarterly or semi-annual collection? Maybe even have some of them be OGL. The balance of Polyhedron's content could then become a leaner, monthly, exclusive magazine for RPGA members, sort of like it was originally. I know Polyhedron wasn't doing well; I guess the only recourse would be to reduce it down even more, or charge more for RPGA memberships. Still, Dungeon wasn't doing well either alone, and if Polyhedron helps it survive, then keep it.
Right now, I like the way Dungeon is. Issue 100 is pretty close to the best one I've seen, and I've been with it since the beginning also. However, I find that I do miss the old issues with non-slick white paper and black and white art. It makes the adventures easier to read and use. Perhaps the slick paper and color throughout helps increase circulation; I don't know. I'm guessing it does increase the cost of the magazine's printing, though. If anyone with the hard facts shows up, maybe they could tell us. Anway, if Dungeon reverted back to non-slick paper and b&w art, that'd be cool with me.
Just some random thoughts.