Centralized version control blues

I am in the process of migrating a SVN repository to Darcs. A couple of the changesets in the SVN repo make baby Jesus cry. They create conflicts such that checking them out in order fails spectacularly and you need to go hands with the working directory to clean everything up before moving on. All of this highlights a rather interesting (though totally predictable) issue that plagues centralized version control.

In Darcs, if a changeset is no good, you can just refuse to pull it. Doing so excludes that patch from your repo and no harm is done (unless, of course, a subsequent patch depends on it). In SVN, given that everybody checks into the same repo, by the time you realise that a patch is going to trip you up, it's already in the bloody database. Now, SVN provides no tools for deleting a specific revision (although I hacked together something that I'll try to toss out there someday) so you can't exclude the changesets that put the DB in an inconsistent state. All of this means that I have been wrestling for the past week and a half trying to get this stupid repository to ignore the "corrupted" changesets. Arrrrgh!