It is really interesting to read about the issues behind developing 3rd party aircraft. I was really wondering why it was that we had amazing 3rd party scenery from different developers but still no aircraft. This seems to explain it quite well.
If anything, I'd be keen on having AFS2 devs put some high priority in improving the SDK and 3rd party support. At this stage I would value a lot more having 3rd party devs starting to offer addon aircraft for this sim than having ATC (still important but not so much in a sim where the aircraft pool can't grow) or more scenery. Just my 2 cents though