I don't think this a was all that terrible a thing. Here why:
1. The source-code leak shouldn't really have anything to do with any delays. In that, it won't cause any delays that wouldn't have already been caused. From what I understand, the anti-cheating technology is the only thing that could delay it, and that is engineered in such a way that changing an algorithm really changes enough to make the new version un-cheatable.
2. Valve isn't really loosing anything here are they? I mean, they still have thier source-code intact, now just someone else has it too. I'de understand if the source-code got deleted, but this way Valve isn't really hurt by the theft.
3. This won't cause any losses in revenue due to licensing the engine. No one is stupid enough to make a commercial game with a stolen engine, so Valve will still get their precious money.
4. What the source-code could be used for, and I hope it is, is to give freeware and independent games a level playing field when it comes to graphics. I think that, aslong as a game is freeware, the source-code should be available to the them free of charge. FRee-ware games are really incapable of competing with the AAA games when it comes to graphics, and whether you care to admit it or not, everyone thinks graphics count. If its all in the name of strengthening the community by making the engine public domain, then I'm all for it.