It would be extremely beneficial for Arma to add two scriptcommands that allow you to exert an external force on an object, in a fashion of
_object externalforce[_xcomponent, _ycomponent, _zcomponent]
_object externaltorque[_xcomponent, _ycomponent, _zcomponent]

The force/torque should apply to the objects Origin Coordinate System and be permanent until manually reset to [0,0,0]

Such a command would offer a totally new level of possibilities to modding.

A few possibilities i could think of right away:
-pushing/pulling of objects by players
-actual trailers for vehicles
-winching vehicles

Even a script based overhaul/prototype for a better fixed wing flight model could be possible with this.