1. Can the FAF altitude be defined as AGL and not MSL (assuming the program knows how to read the terrain elevation) - I know this can be set manually for every airport but this will eliminate the need to do so...
It is AGL
In the manual it states ASL so I guess ASL=AGL? Guess I confused it with MSL
2. ATC request to accelerate descend/climb in case it is predicted you are not getting to the goal altitude at a pre-defined point
Actually it isn't ATC's job to monitor your climb/descend to that degree. Their job is difficult enough, handling many aircraft at the same time, without having to do that as well.
3. Request for expedited takeoff in case there is an aircraft on short final
1. Aircraft flying above FL180 get altimeter settings from ATC
Not really sure what you mean. If you believe this to be an bug please post it separately as I don't wish to expand this thread with such discussions
What I mean is that cruising aircraft above FL180 get an altimeter setting, It is standard above FL180 so why is ATC communicating altimeter settings?
2. ATC priority over other AI traffic (mostly relevant in major hubs & condensed centers) - yesterday I was asked to taxi into position and hold at KATL and got takeoff clearance only after few mins due to the exhaustive chatter/requests coming to/from tower.
Welcome to the real world