Yes. However, I suspect that "fixing" the current pathfinding algorithm could be a fairly large project. A short-term "fix" that could be implemented while the base algo is improved might come in handy for now...
Another solution could be to flag trenches as "buildings" in the code. Just like vehicles know not to drive through buildings (well, most of the time), they could be made to "know" not to drive through trenches. But the ability to add "custom" flagging to the editor might still be a good idea in order for the scenario designer to handle cases not implemented in the exe.