I got my pistols before they buffed the executioner. Once you get into the groove, executioner is really fun.
I have pistols, shotguns, launchers and specials diamond. I am about halfway there on LMGs and snipers, but I am focusing on SMG and AR to get them out of the way,s ince I enjoy the others more. SMG and AR Headshots are the only stumbling block, once I am done with them i am not too concerned with the rest. It's just a matter of time.
I also got diamond pistols before the executioner buff, I did the executioner second to last, saving the first pistol to be my last, wow what a great decision that was.