One can buy bren for that and not suffer the penalty. Mobility nerf that comes with vicker K is simply crippling specially if one tries to use the AT grenade.
Well, that's your opinion.
I think it adds a nice flavor, gives them something extra and keeps them unique defensive troops instead of assault one as opposed to vanila ones.
In fact, I do believe more upgrades should be side-grades like this one, where you get something and lose something not for better performance, but for different one.
At this point very few things are broken yet patches still go ahead to improve the game. The argument hold no water. This change would be an improvement of the current ability.
Why HGB tho?
There is only one player in the whole community who complained about it - you.