Here's a photo showing my interpretation of a 2-vs-2 encounter in a gorge, right as initiative is rolled. When I imagined the scene, I was thinking of two 4th level PCs (a caster and a martial) in an epic+ encounter against a hill giant and an orc (CR 7+). Imagine how such an encounter might play out. With the giant on high ground throwing rocks, and a climb check required to reach him, should they just run? If the 2 PCs are poorly optimized, I think they're in trouble.
The scene features a paver in my own garden—tipped on its edge. The giant's perch is a stone used for edging.