I love using simple rules like DBx and HOTT to execute the battles in a campaign, but I HATE the terrain rules for them. The terrain rules for the older WRG 7th edition rules, and for "Field of Glory" at least have the advantage of not letting the defender set up some iron maiden of terrain, but even before FoG came out, I had evolved a simple, open-ended system for semi-random terrain generation for campaigns.
(Rule will follow one of these days Real Soon Now ...)