I think it just adds clutter. If it's to keep around an old copy, that's what cvs is for. One good idea is to let us write modules. Some of the Java editors have plug-ins. I know my code wont get trashed down the line.
Lets support both.
Why throw away good code every time the wind changes. A XBEL plug-in or pick your own. Yes, your work on Interfaces will allow plug-ins to work. Now all we need is a plug-in manager. Sun is a little disorganized right now IMO, the two major browsers out there are free.