Dear Prof. Dr. Ing. Warmers,
Paparazzi does NOT filter RC unless you specifically ASK for it: e.g. the mode channel of PPM receivers that was often averaged over 10 frames but on modern digital receivers this is not needed anymore: see e.g.: https://github.com/paparazzi/paparazzi/blob/master/conf/radios/R6107SP_7ch.xml
where all averages are set to 0. This "average" value is indeed very important and should be understood before changing or you might add delays.
I analyzed delays not so long ago and the total delay between your RC-receiver to a motor command is never more than 1/46 + 1/512 + 1/400 in the very very worst case and on average half that value: total delay = less than 26 millisecond which is just the rate of normal digital RC gear.
This can be a tuning problem (like low-p / high-d gain), but there is also a reference model which slows down the quadrotor (and makes all quadrotors fly the same way). If this reference model is set slowly (e.g. low angular accelerations) this is very visible during the flight. You should either select a reference model that fits your size multicopter or bypass the reference model altogether.