I've been having serious problems countering Wehr mortars recently, playing as Americans.
They were messed up in 1.71, but still useful to an extent. Now, with T2 Terror being all the craze, practically every game I play features a mortar, and I find myself unable to counter it. My own mortar won't work, as the Axis one has a longer range. Pushing with rifles doesn't work, as there are MGs and grens covering it. Snipers usually aren't an option, since often you cannot flank with them, and you cannot afford to push them to the front line along with other troops.
Take a map like Wrecked Train, for example, and Wehr starting on their usual north. The fighting goes on in the middle, and their mortar can be placed next to the house (that will have an MG inside). Its range is just enough to shell places the Americans use for cover, behind destroyed wagons and debris. The US mortar cannot reach that far without getting destroyed by infantry support. There is no room for a sniper to take a few shots. Not even a quick M8 works, because the smart Wehr player will also park a PaK nearby.
So what do you do to counter a mortar in such circumstances? I can't think of anything (that's why I'm still lvl8, slowly falling back to lvl7).