I understand it is a legitimate concern for many, here, it seems. The "This monster is not tough [enough ergo "sucks"]" has been sung many times. There's a thread right now about the balor and how weak and easy it is. The assumptions of the game on/around which the game was "balanced" (including, but not limited to: multiclassing and feats are optional, there will be a 5 person party, etc...) simply do not play to/stand up against an optimizer/powergamey or 4e-ish style of play. That's for [you/anyone] to work out and adjust as necessary if/when you change those base assumptions. When you [again, anyone, not "you" specifically] change "the rules"....the game changes. For some this is "better" than previous editions, for some this is "worse"...Objectively, of course, it is neither. Its just different. Because it is a different game than it was.
Oh!...and as long as he is holding his wand, Orcey can cast blight every round if he wants to (no charge. As well as animate dead, so those 500HP of summoned critters, they just keep coming back) Name of the game? Get the WAND away from Orcus and you have a very GOOD chance of taking him down. Played[DMed] well, you'll never get near him if you don't separate him from his wand.
I agree, inflict wounds would have made sense also...but I think/they seem to want to be significantly more limiting with "innate magic/spell-like abilities" this go round...particularly when it comes to demons/devils....but fey too...dragons...everyone seems to have gotten an "innate magic" smackdown. But I think he has enough to cause some serious damage in actual play...Keeping in mind, of course, things never being what they seem [theorycraft] either from a "looks OK" or "over-/under-powered" perspective. It all depends on how it is played (by the DM /and/ players).
EDIT: a final thought on "...depends on how it is played..." I, personally, think that is as it should be. "The play's the thing!" and all that.