Way too many trees. The dense forests make it very difficult for tanks to find other tanks, even when they are less than a couple hundred yards away. Sometimes tanks that are virtually on top of each other can't find each other. And when you do find the target you can't get a shot because in AH3 it appears you can't fire between branches, or at least the collision zone for trees vs shells is larger. In addition, the sound localization in AH3 is much more vague (or in many cases just flat out wrong*) that you are looking for enemy tanks in the wrong direction.
A check of Google satellite view of the area around Kursk shows it does not have nearly so many trees. It is mostly open farmland with trees limited to drainage areas between fields. Better texture tile choices would have been 16, 18, or 19 or perhaps 7 or 8 (counting from 0 on the lower left).
(*an enemy tank approached me from my 3 o'clock yet the sound of his engine was clearly at my 12 o'clock.)