Here are some personal suggestions there probably around the forums somewhere but everyone’s doing it. :)
Fms is a great Learning tool and exceptionally good for the price (0.00).
But maybe in time as Fms progresses these touches would really bring the simulator alive.
1) Nitro smoke can be seen from silencers
2) Can cut off the heli and planes engines and the prop comes to a stop.
3) Movement of key features on the Aircraft (mainly control surfaces.)
4) MULTIPLAYER (note in Caps)
5) More Environmental physics included such as having a cushion of air under a heli or ground bumps in the air as you land.
6) With photrealistic scenery that you cant land on the horizon with.
7) Planes have collision points which allow the plane to brake apart.
Maybe for now it’s asking way too much, but have you ever heard the saying in time you can make good progress.