At first glance, this feature should be simple, right? I don't think so. Here are some open questions I have in my mind, along with some features I'd like to see.
How will retweets appear in search results? Will it show the avatar icon of the original poster or of the person who retweeted (or both)?
Duplicates: if more than one friend retweets the same message, do you see all the retweets separately in your timeline or consolidated somehow?
Will retweets be shown separately or consolidated? If shown separately, there will be a lot of duplication. If shown consolidated, you cannot visually get a sense of the retweet volume and time distribution.
Can you add a comment to the original message when you retweet?
Will Twitter track and display a count of the number of times a message has been retweeted?
For a given tweet will you be able to see a list of all of its retweets?
Another question I have is whether a retweet can be retweeted, or if only the original message can be retweeted. I'm guessing they will only allow retweets of the original message, because supporting a hierarchy (threaded/tree structure) gets very complicated. From the screenshots it looks like it will just be flat. Here's why supporting threaded retweets would be complicated.
Would Twitter track and allow you to see an entire chain, so you can see everyone that retweeted it along the way between the original poster and the person you follow?
Could you see other retweet chains, other than just the one that led to you seeing it?
Would a count be tracked for how many times a retweet has subsequently itself been retweeted (i.e. how many children does the child have)?
I don't think the "RT @username" way of retweeting will completely go away, even after Twitter releases the retweet functionality. Here's why.
A lot of Twitter clients already have retweet functionality doing it the old-fashioned way, and it will take some time for them to switch to use Twitter's new API for it.
There will still be times when users want to edit/truncate/abbreviate the content of a message, and/or add some comment of their own.
When you copy/paste the message and post it yourself, your avatar icon shows up in the timeline, instead of the original poster's. This is a minor cosmetic difference, but when it comes to marketing and branding, these subtle details matter.
I'm looking forward to the upcoming changes, and will be very interested to see how they decide to implement it.