If they were to "fix" this "problem" (acknowledging some people see it as such, but I personally don't, and suggest that they wait it out and see how much it affects gameplay before making the call), here's my suggestion.
If teammates/enemies see the glowing gun, fine.
But make it so the player doesn't see their own gun glowing.
Instead, have a faint glow effect around the crosshairs when you have a damage buff - that's what they did in Transformers: War for Cybertron, and it worked perfectly - it was subtle enough not to interfere with your vision/aim, but visible enough that you wouldn't miss it or mistake it for something else.