As I've already disabled the extended line feature it would be easy to disable the 150% fire bonus as well. Instead I've taken away the British Musket and ditto Rifles. Do you think it would be better the other way round? The only way to simulate the effectiveness of British tactics, as I see it, is to give them a fire bonus. Unfortunately this adds to the unrealistically high casualty rates. They should get a melee bonus (in line!), or a melee bonus after firing, or something like that. Which may well open up another can of worms. Perhaps a British Musket that only fires at, say, 150% at the shortest range would do the trick.
Yes, despite it all it is still a very enjoyable game, and the ability to modify many of its features has kept me off the streets for many hours (I think for me this is where most of the entertainment lies, as with PTW and BGW).
In itself the rigidity of the map is not unacceptable to me, seeing it as part of the game's abstractions. Not that it wouldn't be nice to have a bit more variety in terrain types. Modding the map, as you describe it, would be above my capacities. But if there is anyone out there that would want to do it, I've just added an
appendix about the Quatre Bras map which should be a good place to start.