After driving a 2012 Edge this week, I would classify the Edge as being in a different class than the Terrain. Basically, the Edge was made from the ground up on a midsized chassis — and it shows while driving, more than anything. The Terrain and Equinox, meanwhile, have similar dimensions as the Edge but have that compact car feel… in driving, and in options/features as well as luxury amenities/niceties. Soft-touch materials, more interior room (from similar dimensions), and a ton more luxury options…
See, I think the problem is that GM still considers the Equinox/Terrain to be compact crossovers — and treats them as such; instead, it should remake and reposition its crossovers by class (compact vs. midsized) — and utilize appropriate architectures. A Malibu/Epsilon derivative for a mid-sized crossover, and a Cruze/Delta derivative for a compact one.