Wouldn't it be dreamy if you can install fixes and mods with one click rather than having to trudge over to Pcgamingwiki every time or some other place for fixes to games?

...No? It would just slightly change which website I'd have to trudge over for fixes, plus I'm not sure if I could trust GOG to do it right.

Has to remain a pipe dream I'm afraid, that's not within the scope of/what the program is about.
Which is comprehensive large mods and total conversions.

Most fixes are straightforward to implement. It wouldn't be difficult to do. What GOG should consider is offering these fixes as optional extras, giving us the choice to use them, along with clear instructions.

All it would do is impose further workload on modders many of whom have said they don't mind uploading to the two biggest mod sites (Nexus & ModDB), maybe Steam Workshop, but they aren't going to upload to every single minor digital store that wants its own walled garden (GOG included) in addition to all the mod sites on every single update. So we'll end up with half-outdated and half-missing mods that will drive people to same mod sites anyway. Exactly why Daggerfall Unity GOG Version was delisted from GOG due to not being updated:-

"We've made this decision because, at this time, the pack is outdated and no longer fulfills its purpose of providing a hassle-free modded experience to the game."
https://www.gog.com/forum/general/delisting_daggerfall_unity_gog_cut

GOG could just run around the net copy-pasting other mods here from other sites, but that deprives modders themselves of income due to bypassing mod site revenue streams (donation links, fewer Downloads translates to reduced ad revenue / share from a premium subscription, etc). Overall a "GOG Workshop" that ends up hosting a mix of outdated and half-missing mods whilst getting a reputation for screwing modders over (same way how zero-effort "reaction" videos on Youtube take revenue away from original content creators) would be the worst of both worlds. The sad truth is GOG already got it right once with GOG mixes...

Gah, there are X different sites which host game mods and fixes!
Wouldn't it be convenient if GOG hosted all these in one place?
Result: Gah, there are X+1 different sites which host game mods and fixes!

;-)