if i remember correctly the reason why they changed button though was so that you couldnt do the mark + il2 combo and just instagib any tank that doesnt have panzer tactician. i mean guards are a capable combat unit right now, they recieved several buffs with the PTRS AI buff and the fact they dont dance around anymore.
Still it requires from you 2 different abilities, and guards as a support unit.
On the other hand we have Paks wall which can stun and snipe everysingle tank in game without any counter to this ability.
Guard at least did just support job without damage dealing.
Paks do everything on their own.