One very important question has been unequivocally answered: there will be an SDK!
is this indicate if there an SDK?
... The challenge with creating a transparent development process built on collaboration is that we have to work on the foundation for delivering that information before doing so. With that said, we will be kicking off our Feature Exploration Series in the fall where we will be working closely with the community to walk-through the next iteration of Microsoft Flight Simulator in granular detail.