The biggest, and first example, of the Arrowhead devs nerfing a weapon based on user metrics (rather than an understanding of their own game) was the railgun.

At the time (before being nerfed), it was the only effective method at killing the absurd amount of heavy enemies that the game throws at you on the higher difficulties. The game is designed such that heavily armored enemies can't even be damaged by most weapons (since they don't have enough penetration to make it through the armor), which forces the players to pick anti-armor weapons specifically to deal with those heavy enemies. At the time, the railgun was the only effective anti-armor gun the players had. Since the railgun nerf, AH has since buffed the other anti-armor weapons, nerfed heavy enemy spawn (on most missions), and nerfed some heavy enemies to make them easier to kill by those other anti-armor weapons. Since the nerf, almost no one uses the railgun anymore, because every aspect of the gun is better with the other anti-armor options. AH could completely revert the nerf and it wouldn't be considered OP by the standards of the current game.

I should also add that one of the reasons why AH nerfed the railgun was that there was a bug in the game back then where some players could 2 shot bile titans (the biggest heavy enemy threat at the time) with the railgun. And yet, instead of fixing the bug, they decided to nerf the weapon first. AH have also admitted to making gameplay changes based on what they see in Youtube videos from content creators.

The AH devs appear to be both malicious (toward their playerbase) and retarded at the same time. A potent combination of a warning to stay away.