I think these observations of yours are very important, and implementing your ideas would have a significant impact on quality. There are potential problems, of course - for example, some people are simply much faster readers than others - but an algorithm that takes into account a blend of your suggestions would no doubt be superior to the simple upvote system.

I think that the importance of genuine interaction - actual reading and thinking, discussion in comments, interchange among blogs - these things, if measured and measurable, are very significant.

Thanks for a very thought-provoking post! :)