Can't remember if they improved it in the special edition and/or whether it is compatible (same for the mods below) but IMO SkyUI w/ SKSE completely transforms the game - once I got it setup how I wanted it made so many gameplay aspects seamless and the UI vastly better and I really got into the game for awhile compared to my first attempt at playing it which I really didn't enjoy.
Annoyingly I lost my very fine tuned settings for grids and stuff - silly game resets ini files if you change GPU and I hadn't got my latest file backed up - I had the game stable drawing high detail right to the horizon including fixing Z-fighting and drawing high density, high quality trees right to the horizon as well which really enhanced the game.
I was quite conservative modding wise, but as a baseline I think these or something that accomplishes the same is essential along with ENB:
-HighResTexturePack (Official)
-Milky Way Galaxy Texture - makes the night time look 10x better.
-The Cartographers Map Markers
-SkyUI (requires SKSE - also with SKSE installed in steam you have to launch that to start the game rather than launching Skyrim as normal)
-HQ Snow texture (I did try some other snow mods but they were mostly over the top - planning on revisiting that at some point)
-A quality world map with roads (there are better ones but I think that is the best that is on the steam workshop)
-Pure Waters
-Rocks2K Special Edition
-Improved interior lighting (think you need to use one of the realistic lighting mods to make the most of this one but I'm using ENB instead at the moment)
-Immersive saturation boost
You can go on modding it endlessly but IMO especially for a first play through you don't want to go nuts and those address the basic inadequacies of the base game.
Probably not to everyone's tastes but I ended up with quite a moody, end of days, look/feel to the game: