I skimmed through a couple pages and didn't see this mentioned at all but forgive me if it's been mentioned. An interview and tweets from Howard and Hines gave some more info on how the console modding will actually be implemented.
“The plan is that it goes through Bethesda.net, but… outside of things that we would normally take down — we take down things on Steam Workshop if it’s got things that are illegal, or things like that — we’ll do the same thing.”
“Either your nudity or porm, that kind of stuff, or you’re taking assets from Halo, though, Microsoft might allow that. We’d have to get approval. But like, generally, if someone is using assets from another game, we have to say ‘No, you can’t do that.'”
“The idea is you go to play the game and there’s a menu option and you click on it and there’s just a bunch of stuff for you to download. You click on the stuff you want and you start playing the game with these new mods. We want it to be a really streamlined, fun experience.”
Pulled from http://www.inquisitr.com/2852568/what-console-gamers-should-expect-from-fallout-4-mods/
Seems like they're pretty confident in how it will work. This coupled with the already mentioned vanilla save state seems to be a pretty good fallback in case a mod crashes the game. Howard said before that they want us to be able to break the game with mods (hence the backup save state created when using mods).
Thoughts?