I hate to rain on anyone's "this is 4.5!" parade, but the version of the Gauth featured in the Ampersand article is virtually identical to the one already appearing in the Monster Builder; his melee to-hit has actually gone down from +12 to +10, and he's gotten a +2 damage to his fire ray.
The Huge Carrion Crawler is also very similar except for the damages - the attack that's now a 2d12 + 12 was a 1d4+5 in the MM1, absolutely pathetic in a 17th level monster. Interestingly, much of the 'controller' effects are blunted in this new version of the monster. For example, the Monster Builder version imposes a -5 to saves versus its stuns, which was fairly brutal. That penalty doesn't appear in the new version.
So it seems like anyone who has the Monster Builder has these monsters in their new format already, just without the new MM3 era math applied. That's an easy change. And will be corrected when the Adventure Tools essentials update happens. So for those not interested in tokens, this is probably a totally skippable product.
This. I am deeply disappointed with the monster preview. I was expecting the monsters to a lot more dynamic, and simply put, they aren't. Those two monsters just don't feel like Elite's to me - they don't do enough. Hell, I thought even giving the eye rays different ranges (some longer than others) would present more options for using the Gauth. I was originally stoked to by this...now not so much.