It isn't a perfect world, but instead of supporting fully legalized abortion we could see what we could do to attack the heart of the problem - in other words, discuss how to make abortion unnecessary (you know, except in those special circumstances).
I'm talking better, more available contraception and much better sexual education for teenagers. Abstinence-only education is a joke, only I'm pretty sure no one's laughing.
Another thing (and this is just something that's been kicking around in the back of my head) that might help would be to start to break down some of the taboo that surrounds sexual activity. Yes, it's a private thing, but if discussion of it could be conducted comfortably then a lot of the mistakes people make with it could be remedied.
While we may end up disagreeing on the various reasons why abortion is important as a medical and legal option to all women. Your points are very thoughtful, well taken, and of course very good ideas. I would always hope they would be used but in conjunction with leaving the "choice" issue as safe & legal last option.