Finally digging themselves out of the Gamebryo hole in favor of a modern engine.
Bringing in inspired talent to replace their long-stale game design and direction.
Character art that doesn't look like Bethesda hates humans. (To be fair, they might have addressed this in Starfield. Humanoids in past Elder Scrolls games look ugly as hell, though.)
the engine has some quirks but the platform is irreplaceably easy to edit and easy to use with its plugin system, and conflicts with other plugins are simple to handle unlike majority of games that get modded
without that all you have is a bland game with forgettable story and barely any rpg elements, but gamebryo is replaced by another engine and its own bugs and faults
The only reason gamebryo modding is "easy" is because the community has been working on tools for it for decades.
It uses weird proprietary formats nobody else is using and full of stupid quirks. Back when Morrowind released, officially all Bethesda provided along the construction set was their plugin for a thousand-dollar licenced product to make nif models. Nowadays they don't even do that anymore because they know people have been making their own free tools for Blender etc.
As for the modding structure itself, other games support a plugin hierarchy like they do. Rimworld in particular, and it runs on Unity.
Yours is the only praise I think I've ever seen for their approach to conflict resolution. I suppose there's always someone who hasn't been bitten. :)
no gamebryo means modding is likely gone with it
Mod support as good as (or better than) Gamebryo's is always possible, assuming the studio is willing and competent.
Bethesda surely understand how much they have benefited from modding over the years. Skyrim's Anniversary Edition content is built mostly of mods, after all. So it's reasonable to think they would at least consider making it a priority in a new engine.
It's not "some quirks", gamebryo completely killed any ambition in Starfield with how utterly ancient and impractical it is. Most issues with Starfield, even some gameplay issues, boil down to the engine or the things they had to do to try and mitigate its shittiness. This led the modding community to pretty much ditch Starfield, despite how moddable the game is.
And sure, modding will suffer, but other games with different engines manage to have modded content too.
I have lost all interest in playing any future Bethesda games because of their engine. It was pretty crap (but acceptable) back in 2011. Now it feels like a scam to pay for their games. Like one of those "GameStation 5" you can buy on Wish.