What makes you think just changing to leaf spring will prevent death wobble?
Hint: It won't. Death wobble can be caused (or "induced") by a number of factors, but the one thing certain about it is that it affects solid axle trucks and doesn't happen with IFS. The reason it doesn't affect IFS is that it is fundamentally the result of a harmonic, allowing oscillations in one front wheel to be transmitted to the other. If the frequency is right (meaning "wrong"), the oscillations hit a harmonic of the suspension and become mutually reinforcing. This can happen with either coil springs or leaf springs.
If the primary purpose of going to leaves is to avoid death wobble ... forget it. You're on the wrong tack.
Control Arm bushings are the only thing I can think of coming from coils to cause death wobble.
Are bad tire balancing effects considered DW? (Sorry if this looks like a threadjack, just a quick question.)