Dragonzap is not the type of person who is against open-source, and in fact was going to release the source code in the next update (which is probably never going to come).
DCX includes a whole heap of controls that MDX does not, its first version probably wont have everything MDX does however it more than likely will have most. ClickHeRe is an excellent coder, and it sounds very promising.
http://dcx.scriptsdb.org/ is where he hosts alot of the screenshots of his dll in work, and also the help file for the dll (so you can get some understanding on how it is going to work).
MDX is in long need for an update, and there are many capable coders out there other than dragonzap that can do this, however with the source code it is a huge task and ClickHeRe is doing well to produce what he already has. His other dll, rebar.dll which is now ultradock.dll is a great example of how capable ClickHeRe is of producing a thing like DCX (Dialog Control Xtentions)