1) MD was not the 'primary' item released in 2.5. It was an 'addon', which they cannot support, as it would take time away from more important activities.
2) MD was released because it was 'mostly' bug free (there are 1 or 2 glitches, but nothing bad), and had been mentioned in an earlier News article, but no sign of it but to those of L5+ access.
3) Egosoft wanted to give the users a much demanded 'easier alternate' to creating missions. MD does this, it just takes a little practice to get used to.
MD is event driven. If you can imagine an event, the MD can probably use it in a mission.
Since MD can't do some of the more complicated things with objects, it has the ability to run standard X3 scripts to deal with them.
It is upto us users of MD, to find out what can be done, and help others if we can. Egosoft has a full plate in front of them, and cannot allocate the time to 'update' the MD.
I am glad they even THOUGHT to add the MD to 2.5. I liked playing with it, seeing if I could make it 'bark'.