I voted to get rid of that crap. However, after thinking about it, I realized that it should stay. For one, it would be difficult to enforce such a ban of a popular gun.

It is also easy to counter such a gun. If you see a red dot move around the corner then it suddenly disappears, don't run head first. That isn't Halo strategy, its a call of duty move. Instead of rushing ahead, call out to your team. Or maybe you could bank a grenade off a wall to prepare the bolt player for a quick headshot. There are multiple ways to counter a gun like so, but people tend to forget so.

343 even attempts to balance it by having the gun emit a noise while being charged.