Could it be that this plugin overwrites the vanilla flying behaviour?
Cause the flying feels cumbersome after installing the plugin.
The nose always wants to go down after lift off and one tends to crash more often.

Are these values the vanilla ones or your own?

"Lift Fraction": 0.25,
  "Pitch Torque Scale": 400.0,
  "Yaw Torque Scale": 400.0,
  "Roll Torque Scale": 200.0,​

The default configuration is intended to match vanilla. It is possible that Facepunch has changed the vanilla values, but not sure if that happened since that could have been disruptive to players. It is also possible that something else is affecting the flight behavior such as the turret or storage attachments.

As a test, you can set those options to -1.0 to use the vanilla values. The plugin will not modify those properties of the minicopter while the configured values are negative. This test will allow you to determine whether the value of these options was the problem, as opposed to some other feature of the plugin.

The only thing I have active is the light.

I see your reply does not address my suggestion. I still suggest that you try the above configuration change in order to prove or rule out whether the value for those options is the problem.

The mini feels much lighter now. Much better.