A friend of mine actually convinced me otherwise re: youtube comments. Because youtube comments are reverse threaded by time, so the newest comments are first, it encourages comments to be actual reactions to the video instead of just getting lost in replies to replies to replies.
That's a good thing. It's really easy to get lost in comments. In some ways it would be nice to hide all comments until you make one. Though you'll probably end up with a list of the same remarks. In some ways you have that already! (People don't seem to think for themselves any more...)
I always fancied threaded comment systems, but they can spiral off topic. That's not in tiself a bad thing. Loads of comments can be hard to read, or rather take a long time to read. Perhaps a character limit - and a comment limit would make them more succinct and better all round.
Wasn't the +1 just a shortcut for those that used to just cut and paste someone else's comment to signify that they were in agreement with what the other person said anyway? Perhaps I'm wrong and it means something different to other people.
Part of me says do anything to make the YouTube comment system better. But I'm not sure if Google+ is the right way to go about it.
YouTube comments (aside from being a cavalcade of human stupidity) don't even work right. Threads don't work, with replies appearing in random locations rather than indented under the originals (but sometimes they do inexplicably appear correctly). Page breaks are totally wrong, with the same comments appearing on the next page but many of them missing. Really, why even bother. YouTube is a failure of basic design and Google, with all their resources, hasn't been able to field a competent layout. That's pathetic.