Heya, Erik.
I'm probably not the demographic whose response you want, since not only do I buy Dragon, but the recent reorganization has me buying Dungeon again, too. But I'll respond anyway, and pretend the question was, "Why could make you STOP buying Dragon?"
Fiction.
Nothing annoys me more than losing ten pages of gaming content in favor of ten pages of fiction.
I can -- and do -- get speculative fiction from other sources, and I would likewise be pissed off if those other sources spent ten pages of content on gaming. If I buy a fiction magazine or anthology, I do it because I want fiction. When I read Dragon, I do it because I want gaming content.
I firmly believe that the only reason Dragon still publishes fiction is that y'all're afraid to ask the tough question. Instead of asking, "Hey, do you like fiction?" or "do we have enough fiction in the magazine?" you should be asking, "Which would you rather have, fiction or more gaming content?" I have yet to see a Dragon survey ask that question, and I've been around long enough to see a lot of surveys.
So, because I enjoy the rest of the magazine so much, currently the only way to drive me away from Dragon would be to increase the fiction page-count. But if my interest wanes, there will be a point at which I'll drop the magazine because of the fiction, whereas I otherwise would keep subscribing.
I want to stress that my dislike of fiction in Dragon is not a comment on the quality of the fiction in Dragon; for me, the quality is irrelevant. I don't think it should be in the magazine at all.