The main advantage, by far, of this retweet implementation, is that twitter controls everything. The value of the retweet data is astounding. It might make their service viable - compared to the tyranny of chronological views of everyone that could be their downfall.
We need to find good content, and bubble it up. You can't just have realtime to do realtime search. You need content. Currently, twitter has an extremely poor estimate of what is good.
Let me take this opportunity to also gripe that favorites should be MUCH more prominent. They need to incentivize them by showing a count or usernames next to each tweet. And let me reorder tweets based on their being marked a favorite.