That's an advantage when fighting head-on, and only a minor issue when fighting from the side.
Actually, it can help out a lot from the side, too, especially in cases where one ATGM is not enough.
Depending on the scenario, this can be seen as both an advantage, and a problem, sooo, I'unno.
I think the best way to deal with it is try and make it so that should one unit be lost track of in a group of units, the ATGM switches to the next available target in flight that's a part of the same group and tries to adjust trajectory to hit it.
Has Eugen actually said they are going to attempt to address the ATGM inaccuracy?
Well, the most recent patch aimed to try and fix the issue, and it's helped quite a bit to make them more effective and decrease the frequency of the bug, but it's still blatantly there.