Notice that green cover will now affect against explosives. It doesn't care where the shell lands, if you have cover between your unit and the enemy you'll receive the damage mofidier (this also applies to mortars).
Pretty sure it has always been this way, they just removed it for one patch by mistake.
There is a setting in the options menu for the game to disable user content. If you want to delete what you have already downloaded go to the workshop and look for browse subscribed items. Then delete them.
It's fine as it is. If you want more AT power you go for the StuG, a dedicated (and fantastic) AT platform. If you want more AI you go for the Ostwind. If you want pretty good at both you go for the P4.