I'm alright with the lower percentage of non-core-setting modules with my Dungeon magazines. Because the adventures that get published tend to be really, really good. Tend, mind you. Not all the non-core adventures recently have been home runs, of course, but of the three most recent Eberron adventures, I've used two of them. I specifically restarted a campaign to use those two (Murder at Oakbridge and Chimes at Midnight, specifically - I loves me the mysteries!). And the "Man Alone" FR adventure was my favorite high level non-AP adventure published this year.
So, as long as they're good, I don't particularly care if I only get an Eberron or an FR adventure every once in a while. I don't run nearly all the adventures I read anyway.
Demiurge out.