The 9mm M882 round was a matter of politics and not really having proven its worth that got us saddled with that POS round! Round placement is the typical defense I hear from the 9mm crowd but I remember being there (yes, this is first hand accounts) when an M9 put 6 rounds center mass (so much for proper shot placement) on a towlie and didn't slow him down until a burst from the M-60 dropped him in his tracks. This is nothing more than a repeat of the Phillipine Insurection of the last centruy when we found that the .38 Long Colt also had these problems with the Moros. Failures here brought about the .45 ACP and now we've come full circle once again of planning on going back to .45 ACP once again now that the 9mm is proving to be a dismal stopper as well. Those that fail to learn from history....
Now as far as giving one group weapon A and another group of shooters weapon B and those that have special requirements weapon C then a modified version tailored for certain missions weapon D is a logistical nightmare. The Germans found out this problem during WWII which is why we try to standardize everything as much as possible. My wife is a logistics officer and I'm sure she could go on in depth about the problem of logistics in a combat environment and being CATM, I can tell you that you are going to have more problems with parts supply, ammunition accounts, scheduling training classes and maintence issues the more your weapons inventory becomes more diversafied. For instance, I'm in an AFSOC unit. Are we supposed to have one group of weapons, parts, ammunition and classes for the PJs and TAC-P guys, one group of weapons, parts, ammunition and classes for the cops, another group of weapons, parts, ammunition and classes for the pilots and yet another group of weapons, parts, ammunition and classes base populace and then divide that base populace into what, Catagorey A, B, and C shooters or maybe just let them pick what they want? It's just not workable from either a logistical or training standpoint. Sorry but the best thing to do is to find what is going to work well for the widest variety of shooters.