Going to have to disagree here, it makes little sense to offer yet another version of the same game when it's the worst of the bunch. It would just confuse buyers and flood GOG's support team with unnecessary requests.
A more pressing concern to me is how well the GOG version works with mods... because from what I read so far it's got some severe issues that needs fixing.
foxgog: First, the original version ("Legendary Edition") was compatible with more community mods.
[...]
This advantage of the original version is diminishing over time, since quite a lot of the user-created modifications are getting updated/fixed. (By the way, really affected are only the script and DLL-insertion dependent mods! And the community made mod manager tools, since the GOG.com release uses some different folder names/locations.)
You said it well, LE
had the advantage for a few years back when SE was new, nowadays it's the opposite. There are still a few modders who publish LE versions of their works, and some who specialize in converting other people's mods, but the community has largely migrated to SE years ago.
Also it's not just scripts and DLL that are incompatible. 3D model formats (and I think texture compression too) are different. CK form IDs are different. ENBs are incompatible. And there's probably something else I'm forgetting. Bottom line is, converting mods is possible but tedious, not many people are doing it, and unless they learn how to do it themselves, LE players have a much smaller pool of mods to choose from.
Time will tell if SE will also be replaced by AE eventually. Probably not, but TES VI is still a few years away, so who knows...
foxgog: Secondly, the original version still runs on a 32-Bit basis and was not loaded with resource heavier uspcaled textures. Hence, its system requirements/demands are significantly lower, enabling users with older computers to install and play the game! (Both the "Special Edition" and the "Anniversary Edition" utilize and require a 64-Bit system and a more potent graphics solution.)
That's true, but let's not equate low system requirements with "it runs well on weak computers", because it won't. Skyrim LE is very unstable, and the many stability fixes the community created over the years are essentially workarounds to let the engine squeeze more power out of your hardware. Poor hardware = poor performance and less stability.
foxgog: And thirdly, the original version (now "Legendary Edition") has a completely different tone or atmosphere! The "Special Edition" update included not only higher resolution textures, but also changes in the lighting system (both shadows and colors), a shift to a more colorful, autumn-like (orange) ambience with a blue sky, and decrease of the visual impact of harsh weather conditions.
The original "Skyrim" features a harsher, bleak and overall more greyish, darker environment, where bad weather reduces visibility significantly! This atmosphere, which is fitting for the nordic and on top of the world (mountainous region) feel of the game, is lost entirely in the "Special" & "Anniversary Edition".
That's just the standard ugly 'Bethesda style' of the FO3 era: heavy shadows, gray\brown\greenish ambient fog and desaturated textures. I doubt it was carefully designed to fit the nordic environment and it's still present in SE to some extent... but for those who really like it, a good weather mod+ENB combo might yield some very similar results.