The Closed-Beta tester probably can form a better opinion on this, but they can't share with us.
So, what features for UGC would you prioritize? What do you really need to make the type of UGC content you want?
Here is my list of features in rank of priority. There are certainly more then one can think off, but I think these are the top 3 for me.
1.) Ability to create UGC PvP Arena maps.
This isn't really a big feature, in theory. At least the map itself shouldn't be so hard to create (a good map certainly would), but from the UI perspective, there needs to be a way for PvP players to enable a custom map for PvP (be it via a Queue or Challenge).
2.) Dialogue and storyline branches.
Just to get off of the straightforward railroad. There needs to be a way to create puzzles and mysteries and decisions that affect the events and the outcome of the mission.
This seems to be one of the must crucial features to allow players to create compelling PvE missions.
3.) Ability to create PvP Capture & Hold and War Zone maps.
This seems far more complex then an Arena map - you need to be able to do "missions" scripting in a War Zone,and the Capture & Hold logic needs its own logic, too.
The ability to add this "simple" PvP content should already help the PvP community a lot to do something "fresh".