I almost hate to mention a negative reaction to anything about HW:LG, since I love everything else about it and can't wait to buy it. But...
I've read in the manuals that roads and trails are treated just like surrounding terrain and have no effect on movement in the game. I can accept that in small battles, perhaps, but in maps of the "mini-campaign" size, roads should have enormous significance as supply routes, lines of communication, and avenues of advance, retreat, reconnaissance, etc. At a grand-tactical or operational level, roads channel troop movements and greatly shape the eventual battlefield.
If I were playing on a mini-campaign map, the first thing I would do is send my light cavalry to screen all the roads, set outposts overlooking all the likely roads the enemy might use, etc. But if the enemy could move just as easily in any direction on any axis, with roads having no effect, how could a cavalry screen possibly have enough troops in it to be effective?
At Waterloo, why do you think Blucher appeared where he did in the late afternoon? After Ligny, why do you think Blucher was faced with two basic choices about his direction of retreat?
If this unrealistic choice was forced on JMM because of design limits in the game engine, or something like that, then OK. But maybe it can be considered for the next expansion/update? Just don't pretend it's a small and unnecessary detail, and therefore not represented in the game.