Eric, the stainless prop pictured above is a 14x16 (Im sure thats what you meant), and I can definitely see the resemblance to the older 3-blade legend design. Your 12" 3-blades still work great on the smaller, lighter vintage CC's. No idea how old this one is, but the shape is pretty much the same.
I can see how thinner blades would make a prop faster (more efficient). I cant say Ive ever noticed any fatigue on any of my CNC props, but I guess we'll see how they stand up to the test of time! Luckily I dont run in a river or lake with any real debris concerns.
I cant say I agree with you on the last few hundred rpm's not adding any speed. I think I understand what youre saying though. The more wetted surface a hull has, the more RPM it takes to push it faster- especially at the high end... so youre getting less speed per extra rpm at the top than you do in the midrange. Still, to say that the last 300-400 rpm can return next to no measurable speed increase seems to be a real stretch. That has not been my experience with the brand X props.
I do realize that there are several parameters that are different in the 2 prop designs, which are not easily measured or communicated I dont have a understanding of how pitch distribution will affect performance, but I do recognize that aft rake will help top end speed by lifting the bow slightly. Whether or not the Acme design is a "work boat type prop" really doesnt matter much to me, I just want the best performance out of my non-100mph ski boats.