Hmm... perhaps I'll expand a bit then.
The reason why I said terrain is less important in 3E is because there weren't many ways to interact with it - unless you were a wizard. It was difficult (and rare) to have abilities that allowed you to move enemies about freely, or to better position your own allies. At best you used a collection of scrolls and items to achieve battlefield superiority (by flying, usually) - things like moving bad guys out of cover or placing difficult terrain between you and your opponents weren't really optimal strategies.
In any case, I see little mention of terrain effects in the 3E Core, and none of the modules I've played make substantial use of terrain effects. It just never seemed to be a central concern of the system as a whole. Has your experience been different?