All I'm gonna do is ask how the heck the Ogre Mage fits into this criticism.
*What* flavor? What "classic" feel? What about him was so great and so special?
Mearls' criticism -- echoed by other designers in other columns -- is that if you look at the original Ogre Mage he's a hodgepodge of essentially random SLAs that were *originally* chosen by cherrypicking various random magical powers various oni have been said to have in Japanese folklore. Since none of them are really centered around a single folkloric concept or story element, an ogre with sorcerer levels is a lot more true to the original concept of an oni (a big ugly guy with unpredictable magic powers) than the One-Trick Ogre Mage.
As Mearls' pointed out, the mechanical use of the Ogre Mage (fly in, blast with cone of cold, turn gaseous and run away) doesn't even match the actual flavor text and illustration, where he's shown being a muscular badass with a greatsword and being a cunning leader of other ogres. Certainly this whole Ogre Mage as Master Manipulator thing isn't in there. Does it *say* you're supposed to find Ogre Mages masquerading as the new prince? Does it *say* he has a bunch of innocent human peasant slaves who will defend him? This isn't real flavor -- it's retconned flavor made to match the OM's ill-chosen abilities. It doesn't even work that well -- as opposed to a monster who actually has abilities that *reliably* work to mess with people's minds, like _dominate_ and _modify memory_ and whatnot, he just has the single _charm_ spell, which has the unpredictable effect of making people like you. (Unless you're going to unbalance the game horribly in favor of your bard PC, _charm_ does *not* function as any kind of mind control or coercion or make anyone do anything they wouldn't normally do.)
You have to write a whole, big, long, complicated story to justify why an Ogre Mage has a bunch of town guards defending him. It isn't a natural part of the Ogre Mage's defined abilities, and, moreover, it kind of contradicts the Ogre Mage's defined flavor as such. (Don't the typical encounter stats say he hangs out with other ogres? Isn't his environment in the wilderness? Doesn't the illustration show him all tattooed and whacking things with his sword?)
The master-manipulator Ogre Mage isn't a basic part of the OM's flavor, it's something DMs can come up with as a creative way to use the OM's powers, and today, thanks to 3.5's greater modularity, a DM can do that by adding class levels or homebrew SLAs to a monster if he so chooses. Nothing has been sacrificed of the OM's *actual* flavor -- he's just been altered to *fit* the flavor he actually has in the text.