IMHO, Dragon worked best when it catered to all the fans by giving them a breadth of material. That meant regular 'monster' stuff for the DMs who wanted to throw something new at their players ("Creature Catalogs", "The Ecology of ..."), regular FR articles for the fans of that setting without necessarily having to do a 'series' ("Rogue Stones and Gem Jumping", "City of Sunken Spires", "Seven Swords"), regular GH/DL/Mystara et. al. articles for the fans of those settings, and enough non-gameworld specific material to stop the griping from the anti-FR/GH/DL etc. brigade. I was always interested in material that could be instantly used in any campaign like new herbs, poisons, horses - even if that material was showcased in a gameworld specific vehicle (like GH or FR) - it was very simple to take it out of the 'fluff'. And at the very least, the 'fluff' was usually interesting and entertaining and with a bit of work could be transported to other campaign settings. Certainly better than a bland, dry schoolbook recitation of game stats.