The Bethsoft games have a really huge and very well-established modding community. I'd say if anything their modding would be actually quite a bit more difficult than it is with the Original Sins without the community in question as so much stuff had to be figured out with very little information and a lot of tools created to make the modding system actually functional. To a certain degree there are parallels, such as with Norbyte's extractor and converter which is pretty much essential, but it seems that the Larian games are more "moddable" from the get-go.
That said, I haven't done very much other than outfits, and I admit to being somewhat perplexed by the Divinity Engine. But it was a lot easier than modding Divinity II which was... well, it was a challenge, put it that way.
