The ogre hp boost before the turning would be balanced out with the *2 damage theorycraft too, yes. That's all well and good, but what about autosneak from drow? Autofly? Fury? Physical resist? And so on? Fortunately some things such as slith autotrip are hard coded for that race and that race alone. Could you imagine illithid shock working for the undead? Yummy!
Part of the reason for exp penalties is the bonuses you get from the specified race. Increasing the undead penalty would adjust for that a little sure, though not all abilities are created equal. You'd be undercompensating for some while overcompensating for others no matter how much or little is added. In any case, that would only ensure you picked a base race with an ability, throwing humans and other races that offer little to nothing by the wayside.
And then if all mages were to be allowed to become a lich, why would you ever play a human? Granted, many don't play humans unless they're playing a monk or going for a qthing anyway, but with those two gone, you're left with just vamp and demon wannabes to an already underplayed race.
Don't get me wrong, I think the idea is awesome. It would just take some balancing work. And by some, I mean potentially significant. You're right when you say it's not something that the staff can't handle, but we are talking about a race (and in the case of liches, race/class) that's already fairly restricted as it is.
