While rebalancing can be good, DICE is the only company can seem to do it correctly. Thats possibly because so many variables go into their game mechanics, and the attention to detail put into the core of the game makes it possible.
Autorifles are king in just about every FPS... its just the way it is. Its the reason they are what every military uses in combat as their main infantry weapon. Its great at all ranges, and is the ultimate multipurpose weapon system. When this happened in Destiny, Bungie nerfed ARs so hard that practically NO ONE uses them even in PvE because they were so shit compared to HC and shotguns... naturally these took the AR's place in crucible because the maps are generally small and hardly ever wide open.... so shotguns get nerfed, HC gets nerfed, and Pulse Rifles like Red Death, The Messenger, and its successors in Y2 take its place as king.... People are always going to gravitate to what they feel is the most powerful weapon/easiest way to get kills. Nerfing ARs to uselessness is never the answer.
Balancing is mishandled by just about everyone these days due to a loud minority of QQers in games that get mad at something that kills them a lot... instead of learning how to counter it, they just want it nerfed now. I see it in Guild Wars, I see it in FPS games, I see it everywhere. My first really bad experience with a nerf that killed the game for me was the FAL nerf in BO2... I've talked about it enough not to go into it again. The work that had to be put into getting that gun to where it was, was no easy feat, and to have that hard work taken away was demoralizing. It wasn't an exploit like the SUPER OP Models from MW2 that were justifiably nerfed... it was just a damn good gun that was crazy deadly in the right hands. The community isn't always right about nerfs, but sadly those that can spend time on a reddit or forum and rally people to their cause can change a game for the worse... and I blame the business model of gaming for that. They want their playerbase to buy DLC, so they are going to be more willing to bend to the loudest voice.