I wonder who would get the eventual credit of a RT. Say I follow userA and userB, both Retweeted a tweet from userC, whom I'm not following. Do I see two tweets from userC from the new home timeline? If so, then with the implied implementation it would be confusing to users as the they are seeing the exact same tweet from the same userC more than once. Image if there are tens of those retweets that can fill up a whole page, will look like spam. If I only see one instance of userC's tweet, then who gets the credit of retweeter? userA or userB?
But overall, I like the idea that Retweet is being recognized officially by Twitter and actually being tracked as well. It might be a little bit confusing to users at first, but it shouldn't take them long to adopt. I think it's better to keep it as simple as possible, after all it's just retweet. conversations can be tracked by other means (like @replies), If we mix RT with conversation, then it would be too complicated for regular users to understand and developers to present on UI