I took a stab at creating a zone system for combat. I wanted to make sure that there were simple mechanisms to dial up or down the tactical complexity from combat to combat. This way, a quick random encounter can be easily handled and resolved while a more important battle could be arrayed out on a battlemap and really delved into. I think this achieves that while still presenting tactically interesting opportunities for movement throughout combat.
Check it out here.
I'm not 100% convinced this is the way I want to go, but it actually does have a lot of strengths and would probably provide a more cinematic experience with less reliance on "pixel bitching" (as Veritomancer so aptly put it). The idea of bull rushing someone into a different zone, especially if that zone is a cliff, seems pretty awesome. Thanks in advance to all the commenters in the tactical movement thread--I hadn't really conceived of zones before your introduction and most of your recommendations got incorporated into this initial look at zonal combat.
I'll try and answer any questions in the comments below.