Divestiture may be part of the picture longer term, but DL needs the capacity right now and the plan is to shed the old CRJs and have an all CR9 fleet within the next couple of years.
The comparison to Comair may not be fair; there were some unique issues there including liability for the 2006 Lexington accident.
Boy I really hope so - I have to fly DTW-GSP regularly, and the CR2's are dreadful on that route (and expensive to boot).