Patience, Bart! Sometimes it takes awhile to think on an idea.
Mackenzie and Colt both wrote about the importance of memorability, and variety of what I think you mean as "environment" (as opposed to "terrain") certainly will help with that. I do think terrain movement (including landforms, natural hazards, etc) is really important to creating a memorable course, with different types of challenges. But my strong personal preference is for variety of terrain in a homogeneous environment.
Take a links for example. When the course gets into a different environment it's getting off the linksland, and personally I can't think of a single non-links hole on a links that is remotely close to a personal favorite. That's even considering that some of those holes would stand up well if placed in a parkland course.
Places like Noordwijkse, Prairie Dunes, Lundin Links, and Cruden Bay all suffer in my estimation.
This seems like one of those issues where there's no right answer, it's just down to preference.
Mark