I used to be skeptical of mechanicals as well. I figured that there was enough that could go wrong bow hunting without the possibility of a blade not opening. I broke down and bought a set of 125 grain rage 2 blades and haven't looked back! With the way they open there is really no chance they won't deploy and they have a chisel tip just like the old muzzys.
My concern is not them not opening but limited penetration if a shot goes wrong and hits bone.
I can definetly see where you could be concerned about that and trust me I get your side of the argument. I don't worry too much with that because my arrow is heavy enough already with my draw length. I don't want to sway you either way but I know that the Rage is definetly a killer and they fly a ton better than a fixed IMO.
I realize a lot of guys shoot mechanicals because they fly like a field point. I shoot recurves and longbows and am positively anal about tuning. The broadheads I shoot will perfectly group with field points.
I do a lot of bareshaft tuning and have seen trad guys that didn't know about proper tuning strip their feathers and find out they were shooting a shaft way out of tune. I've seen them so bad that bareshafts would hit a bag sideways at 10 yards yet they looked fairly good with feathers. After we got these guys shooting the correct shafts they suddenly found their arrows penetrating a lot farther in their targets.
I often wonder if compound guys are way out of tune with their arrows, especially if they feel the need to shoot mechanicals just because they shoot so much better. I think if the shafts were tuned to the bow they wouldn't have the problem of broads impacting differently than field points, except for a few broadheads that just don't fly well. I wonder if the combination of a poorly tuned shaft, and a mechanical which requires more force to penetrate well, cause a disaster on an animal.
