You've probably tried this already, but for an overly sensitive (or too easy to move) stick, try setting the control deflection at VERY low numbers on the left side of the curve, i.e. don't even get up to 10% control deflection until you're at 50% stick throw. Then curve up to 100% at the right side. Set it up so that when you're in a turnfight, with half stick deflection, a small movement produces a very small control deflection (slope < 1).
An old kludge solution was to wrap a bunch of rubber bands on the stick to increase the resistance to movement. If you're an engineer-type, you could also try lengthening the "stick" part of the joystick, so that a 1" movement of the stick produces a smaller movement of the potentiometer than it did with the original stick movement. Always wanted to try building a floor-mounted stick, which would give MUCH finer control, but never had the guts to chop up a new joystick to do it
As for perk planes, won't that mean that the "best" pilots end up in the best planes, and the weaker pilots never get to fly em? That might have been historical I guess (but only for the Axis--Allied "dweebs" got to fly P-51Ds)
but it doesn't sound like a good "gameplay" measure. Encouraging guys to try to stay alive is fine, but "forcing" them to do it in order to "earn" better planes only works if they actually CAN stay alive. A guy who isn't that great NOW isn't going to fare much better when he's being gang-banged by aces in superduperplanes
--jedi