With the changes to vehicles, Engineers have felt rather frustrating to play. As the RPGs in particular seem to do little against them. And the health regen is too strong on tanks as well.
To balance the tanks i feel like RPG damage as follows is a good place to start.
RPG shot to the rear 40% of max vehicle hp per shot, side or top down 30% of max hp per shot, front armour 20% of max hp per shot. Shots fired within a 90° angle of perfectly side on do 100% of this damage, greater than 90° deal 80% of this damage. so 40% becomes 32%, 30% becomes 24% and 20% becomes 16%.
And we really need to update the vehicle states. 100%~51% hp vehicle functions normally.
50%~25% semi-critical state, reduced health recovery by 50% and movement speed by 25%.
24%~1% critical state, Reduced health recovery by 75%, movement speed by 50%, turret speed reduced by 25%.
While it might not be perfect, it'd be a step in the right direction.