HKS has an entirely different system for allocating classes, but it's probably even worse. I think that, at a certain point, when we're thinking about allocation of scarce goods, we have to wonder why they're scarce in the first place. Why does everyone want to take the same few classes? In some areas, we just don't have enough really solid teachers. (They're all good scholars, I'm sure, but I'm talking about teaching ability here.)
In Con Law, I think HLS is doing a decent job. Even if you don't take 14th with Klarman, your alternatives are pretty good (Feldman, etc.). In some of the other subjects (Tax, to some extent Corporations and Evidence), it's a lot worse. There are people who say — and I think this is not entirely fair — that if you don't take Tax with Warren, you may as well not take it at all. Thus, Warren's Tax is unreasonably hard to get into.
That being said, I've been successful so far at putting together a class schedule that I liked each semester, and it looks like next year is going to work out pretty well, too. I bid pretty ambitiously on the assumption that waitlists would move kind of a lot, especially for the spring, so, as a consequence, I might end up with nothing that I want in the spring (I have nothing now), but that probably won't happen.