One of the reasons for upgrading to Movable Type V3.x was that I have been using Jay Allen's great MT-Blacklist module to keep the blog spam away, and the new one for Movable Type V3.x is much nicer. In the long run, I can't see Jay putting much effort into Movable Type V2.x support.
Having upgraded, then came the bad news: the new MT-Blacklist requires a later version of Perl than the one running on my public server. And it's a Cobalt RaQ4, on which the remote administrative GUI dies if you upgrade Perl. Oops. Guess I should have read the requirements a bit more closely.
Given the amount of time required to get this far, I'm not going to revert to Movable Type V2.x. Instead, I have enabled the comment registration facility: in order to comment on the site, you now have to register with TypeKey and sign in. That's free, and a one-time operation for all the Movable Type V3.x and TypePad blogs you comment on, but it is a bit more of a hassle. I'm sorry to put people through this, but I think it's the best compromise for now.