Actually, the upgrade is meant for more emplacement centric gameplay and their maintenance, where LMG would serve them in defending from garrisoned emplacement and getting churchills back into the fight quicker. No identitiy crisis here, just incapability to identify units role.
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.
The upgrade is also rather expensive for a "support" oriented upgrade.
Why fix what isn't broken?
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.