Similar for me Cooley,
I fly spits and Corsairs, and the pictch always seems nice and smooth,
and in PonyD and p38! it seems way too bouncy and poor reactive.
I'm using the ch fighterstick and CH pedals.
It's a combination of 3 things...1) Flight characteristic and stick force differences between the planes 2) stick scaling and 3) ham fisted at the controls.
Reason #1 is obvious, each plane has its own unique flight characteristic and each plane has different stick forces. The input needed to move the flight surfaces will vary depending on the plane and other factors such as speed and altitude. Stick force is the force needed to move the stick so the flight surfaces move, this too can be influenced by different factors such as speed.
Reason #2, stick scaling. The bouncing you describe is a good indicator that you need to adjust the stick scaling for your controls to help smooth out the inputs.
Reason #3 being ham fisted. Some players are applying too much force on their joystick when maneuvering their plane and not being "light" on the controls. Remember, flight sticks in the game might be modeled with stick forces, your joystick isn't. Think of your joystick as a "fly by wire" controller, which it is and you have to be "light" on the controls or you will "over steer" your plane. Stick scaling can help somewhat in countering this but won't eliminate it entirely, so it's important that you teach yourself to be lighter on the controls.
ack-ack