RCP has a new story out about one drawback of either eliminating supers or limiting their flexibility re: who they can vote for. You increase the chances of a contested convention:link
If the Dems are going to limit the options for supers, they should think through some other ways to either prevent a contested convention or make it run smoothly. Because the fact that the Dems use proportional allocation for their delegate allocation makes a contested con more likely for them than it is for the GOP.
The other thing that people don't really talk about with supers is what about the role of delegates for candidates who've dropped out? Don't they become free agents as well once the candidate they're pledged to is out of the race? Doesn't that also present some problems re: how democratic the process is, and is there any way to fix it?