Not familiar with OA, but an Ogre Mage that was actually faithful to the Japanese oni would be quite a bit more powerful than either the original Ogre Mage (which was, face it, a really crappy and hamhanded way of trying to simulate an oni, which they had the nerve to call "the Japanese ogre", which *already* showed their problem with the concept) or this new, spiffy Ogre Mage.
Oni are, after all, spirits who are essentially tied to elemental forces, immensely powerful and feared, control the weather, combat other forms of evil spirits on a regular basis, and so on. Not a CR 8 Giant with wacky SLAs. I would imagine, or hope, that OA's oni are more diverse, flavorful, intelligent and flexible than the original Ogre Mage.
Mearls' Ogre Mage is *just as good* for what it does as the original Ogre Mage -- make an ogre-based spellcaster/fighter-type character (I don't know about you, but the *flavor* of Ogre Magi always screamed "gish" to me, not "vampire-like master manipulator") who is vaguely Japanese oni-*inspired* in what he does. The flying and invisibility still works for that, and contrary to what some people seem to think, _lightning bolt_ is a *better* fit for an oni than _cone of cold_ as an ability, since oni are traditionally linked to thunderstorms more often than they're linked to ice or snow. And, in fact, oni's cleverness are usually linked to their brutality and strength -- the Ogre Mage was inspired by oni in the first place because in Japanese culture the oni is used as a representation of raw, untamed forces of nature -- so the Sneak Attack damage and such makes more sense for depicting an oni than any ability that involves oni taking over people's minds and seducing them and crap. That's far more a tengu-style thing than an oni-style thing -- oni don't use magic to manipulate and seduce you, they use it to beat the crap out of you. They're spirits of war and strength, not trickster spirits. Like all spirits they have a weird, tricksy side to them -- they appear, they vanish, they cause trouble beyond what their mere physical actions would indicate -- but they are, indeed, closer to the European folklore about the Ogre and the Giant than the Faerie.
![:]](http://www.enworld.org/forum/images/smilies/devious.png "Devious :]")
