Diaphragm vs. Borg and Beck.............

Nothing wrong with a modern diaphragm. Less pedal pressure per pound of clamp pressure due to less friction at the pivot points. Also the diaphragm style PP spring design gradually gains a little clamp pressure as the disc wears, until the disc is worn to around the 1/2 way point. Beyond that, clamp pressure begins to gradually work it's way back down. By the time the disc needs replacement, clamp pressure is about what it was when the disc was new.

Any PP that uses coil springs is going to lose clamp pressure from day 1 as the disc wears. The typical way to increase clamp pressure for performance applications is to increase the coil spring's rate. The higher the coil spring's rate, the faster the rate that the PP will lose clamp pressure as the disc wears. For that reason you have to choose a PP with too much clamp pressure when it's new, so that you will have enough clamp pressure to handle the engine's torque when the disc is worn. In my opinion, overly aggressive clutch engagement due to excessive clamp pressure is the leading cause of stick cars breaking parts, also the reason many can't figure out how to successfully run sticky radials at the drag strip.

Another thing to think about if you plan WOT shifts at hi rpms, any pressure plate that features any sort of centrifugal assist is going to hit the drivetrain hardest after the shift, making it more likely to break parts or knock the tires loose.