I not ashamed to admit i was an armor lock user in Reach.
There's no shame. I used it. It benefited me while traversing the field and avoiding road kill and rockets/ grenades. It was fantastic. You have to remember that the community -- people in general, are sheep. I'm guilty. All it takes is one person to say "Hey, I'm tired of dying, this sucks! Why is this even in the game!" and people will rally, unconsciously. I doubt that many people who are responsible for nerfing a weapon, or feature really have a genuine thought on the matter. It flies by word of mouth, simply. The same as how, one person will tell you something that someone else said, but by time it reaches 10 other peoples ears, via, multiple people, the story has gotten embellished, over embellished, exaggerated and skewed to where it is no longer even remotely true.
When a PVP community nerfs a certain weapon, it's usually out of jealousy because maybe it's rare and they don't have it and are tired of getting killed by it as a reminder, or it's a weapon or item they never got good with using and don't have the patience for, but others may get great at using and so, if nobody can have it/ be good at it, then we better have it nerfed/ removed. It's a bitter, bitter world ;)
Shotguns and pistols are a good example of something hard to get right and that were never an issue to begin with. People prefer full-auto or rail guns(DMR/ sniper). The pistol represents a weapon that is hard to use and people can be real good at using, but others don't have the patience for. Shotguns represent a play style of stealth and close encounters, and people prefer being active and bouncing around. These two things will likely see many nerfs throughout any given game and the life of Halo 5. To appease BR and Assault rifle users.