Ambitious, but it feels like science fiction right now. The principles seem reasonable, but we have no reason to believe that SpaceX is capable of pulling this off in the foreseeable future. We'll see if Musk can convincingly explain it in his speech in 40 minutes.
Also interesting to note how close fan speculation actually got to the truth: http://imgur.com/a/87OOT
I don't think seeing them as soulless capsules is a very productive attitude. It's true that Dream Chaser's lifting body design looks sexy, but I don't think the goal of human spaceflight is to be sexy.
From a tech perspective, and keeping in mind that I can presume the goal of human spaceflight to be to push humanity further into the cosmos, I see one thing really exciting about Dragon 2 that CST-100 doesn't have--propulsive landing. A NASA Ames research team says that Dragon 2 thrown by Falcon Heavy could execute a fully propulsive EDL on Mars. This seems like interesting heritage to build, and shows that development of Dragon 2 could have implications on further spaceflight.
This is not confirmed by SpaceX, but has been floating around the internet as the suspected reason.
Last year, SpaceX attempted a first stage water landing, but was not successful. Their two most recent successes on this front had at least two hardware differences from that old attempt: landing legs and heavier duty RCS thrusters. However, due to some combination of manufacturing and launch scheduling, an old core without these improvements, similar to their attempt last year, will be flying on flight 13.
I speculate that this one iced up because the vehicle flew a much higher trajectory than the previous vehicle, as visually noticed from the launch webcast. This meant that the first stage spent more time higher in the atmosphere.
Also interesting to note how close fan speculation actually got to the truth: http://imgur.com/a/87OOT