I agree, and would like to see a change like that in Q&A, but it would be a pretty big deal at this point in the site's life. However, the new Documentation section does a much better job with this. Each edit is worth +2, and upvotes give points to all significant contributors (+5 or +1 depending on size of contribution), not just the author!

This system has had some issues and may still be adjusted, but I think it's a lot closer to the mark. I've probably gained close to 1000 rep so far from documentation I contributed to but did not author.

This is fair. I think it's +2 for an accepted edit vs +10*n upvotes +15 for accepted. Another approach is to just make a new answer on the original question later. I see that a lot for Python 2/3 stuff too.