I'm finding a lot of MS stuff gets released half-finished and then the next release includes all these great features that should really have been in the original, the Entity Framework is a prime example.
Hopefully MS Flight will see a lot of the things that should have been in FSX make it finally and we'll have proper indexing of scenery and planes so the interface is fast and proper use of the graphics card, memory and cpu to give excellent performance on modest systems. We'll have to wait and see I guess.
I agree it's irritating, by the time I've loaded FSX, selected the plane and got on the runway my hour to fly is often down to 30 mins - which isn't long enough to really get anywhere!