You do realize tanks were designed for open terrain. One of the reasons why Arden worked the first time, and nearly worked the second time is the terrain was considered impassible by armor. Both times was a huge gamble by the Axis going through this area, both getting stuck in mud/muck as well as getting bogged down by the trees themselves and slowing their columns making them easy fodder for air power.
The only reason why the battle of the bulge continued as long as it did was poor weather that kept Allied attack planes from bombing the armored columns, allowing them to move unimpeded. They would have been fodder for the air corps if they were able to fly.
How about we get rid of dar, but add in random instances of your tracks coming off, or falling into a mud-bog, getting completely blocked off by dense foliage making advance impossible, and retreat a slow and arduous task? I mean, if we want to go for realism and keep your uberdense trees, this to me seems the most fair and realistic.