Twitter is planning to make retweets part of the API, but the way they are planning to do it fundamentally misunderstands the way people are retweeting. Sometimes, people want to just amplify exactly what the other person is saying. Twitter's proposed changes handle that well. But people are also using RT to add an additional comment, sometimes as simple as "wow," and sometimes it's more of a public reply like this retweet from me:
"it's rude *not* to tweet during #wlip RT @baratunde If I live tweet during We Live In Public, will the universe collapse? #wlip"
Dan Zarrella goes more into the specifics of what's wrong with the proposed changes.
With act.ly and Tweet Progress, I've spent a good deal of time with the Twitter API, and I think there is a very elegant solution to this problem that also fixes replies.
In the same way that Twitter ditched "replies" for "mentions", they should ditch the concept of a reply to a tweet, and instead let people "attach" or "refer" to a specific tweet, which would then be included along with the new tweet.
This fixes a number of different problems.
1. It handles all the situations that RT is currently being used
2. It gives people a full 140 characters to respond or add their own commentary to another tweet.
3. Conversation threading, which is currently a total mess, is now much more explicit and will probably even work.
This is a good user experience because some third party clients are trying to do it, but it doesn't work very well because it's basically guess work. Twitter can make this explicit and solve several problems at once, rather than create a new problem by mangling retweets.