I think a key difference is Dolly is the main "character/mascot" at Dollywood. Lots of merchandising with her name, face, etc. (at least in the park). The actual characters (Benjamin Bear, Flit & Flutter, etc.) at Dollywood are not as easy to find around the park, compared to Disney characters. When Dolly shows up at the park (which she has done quite a bit in the past several weeks due to the filming of the Christmas TV special, there is almost always a parade and passholders go nuts on the forums trying to guess when she will be at the park and are ready to head over to catch a glimpse (or photo) of her. Oh, and a select few even get to see her at the Dreammore resort when she stays in town.
Walt, OTOH, never really was a "character" at any park. Mickey and gang are more popular and really the mascots of the parks. There is almost no merchandising with Walt, other than select items with Walt and Mickey together. Even when Walt was alive, who would people expect to see - Walt or Mickey?