Aaaaah, zombie!
Welcome back Two Shingen.
In regards to DTG, their DLC is rather hit and miss of late, however they are fairly open in regards to other developers generating content, and good at updating the base game for free...although the updates are rather small since any major updates would break all the DLC...
I guess in a way it will be just like the old days of FSX, the main developer created content will be fairly basic in quality, and it'll be up to 3rd party developers (like Accusim and Just Flight) to bring the good stuff to the yard.