I think it's a great announcement - I applaud the effort they're sinking into it.
Might be a good strategy as well. Release a tightly controlled, fully self contained first version (DTG Flight School), which will serve to not only gain new customers but to test new technologies without the added complexity of dealing with third party addons. Then, once the platform is refined slightly, and they have some experience with how it's being perceived, they release what they are describing as a 'proper' full flight sim (DTG Flight Simulator) complete with, we're presuming, third party support.
The fact that they're releasing two separate, but closely related, flight simulators is going to confuse the heck out of everyone however, and likely make any thread like this a mess as people weigh in on either or both versions!