We’ve played lots of Arnhem games over the years and this had some clever mechanisms. We liked the simplicity of terrain To Hit numbers, even if units tended to act identical. The intrusion attacks are an interesting effort to insert a version of an overrun attack into an area game. Blowing up bridges, or diffusing explosives, adds a nice tension to the pace.
The Europa system from GDW/GRD was probably the most ambitious game system from a size perspective: If I recall rightly, 16 miles to the hex with division counters supplemented by regiments and battalions; aircraft at group level (or is it squadrons?)