I remember this being mentioned for Aerofly FS 1, but it still applies to version 2: in many airplanes the wheel brakes are much too weak.
For example, in the Cessna 172, applying full braking cannot hold the airplane in position even at less than half the available power. This can be annoying, e.g. when doing an engine run-up procedure. Also you cannot lock the wheels while braking in any of the airplanes. In many cases now full braking power can be applied, whereas in reality this would not be recommended.
I understand that for a more realistic braking simulation, certain additional aspects will have to be modelled (ABS?).