For me it makes a little sense mechanic wise when you think that we have numerous enemies local to the frozen regions of Skyrim but not as many purely local to areas like the Rift and the Reach. Like the Frozen regions have the Frost Troll and the white frostbite spider, ice wraiths, wisp mothers etc. For non forested regions we have a normal troll, and non frost versions of wolves, sabre cats, bears etc. Besides Trolls and Spriggans the forested regions have very little in the way of indigenous threats. I think adding a wendigo at level 40-50 with a lot of health and a crap tonne of damage resistance and a really high pitched howl that sounds more like a shriek than anything else (ties into the fact that they were intended to be werewolves.) As someone mentioned before Bethesda really should add a horror element, I love suspense haha. We know they can do it, remember the Dunwich building in Fallout 3? That [censored] was terrifying lol
I'm not sure about the Dunwich building though those mutants who crawl on multiple human arms convince me that Bethesda can make something like this. I had one come out of nowhere at me during night while the Nightkin are shooting rockets at me. I turn around in game and almost jump out of my seat. lol