This will not cut out "the middle man" for most developper. Most of them depend on a publisher to pay for their salary for the few year they spend developping the game. So there's no way to publisher will let them sell the game without them making the same profit.
If the game would really cost less when downloaded, then it could be worth it. But for only 10$ less, I'd rather have a shinny box with my manual (of course, they've been cutting on that too in the last few years...).
The fact that HL CD-Key system sucks doesn't mean that there aren't any good CD-Key system out there.
Oh, and if I really can diseable every feature from the thing (yay!), then why would I need to let it run in the background always wondering if it's sneaking up on me (alright, that did end up a little paranoiac).