Wings and fins, (In SR2, SimplePlanes and KSP), move by "magic"
It would be more realistic to have these working, by hydraulic fluids! That means that if in your craft there was 0 hydraulic fluid, your fins and wings will not move.
If the deflection angle and deflection speed are set with more angle/speed, it would requiere more hydraulic fluid, this could challenge plane builders way more!
This could also work with motors, rotators and hinges, just like Falcon 9's gridfins.
and even with RealPlumbing you have to put pipes all the way down