I'm, admittedly, a turn-based purist. I tried to play Fallout 3 several years after it came out (I bought it for <$10 for the complete edition on Steam) and I hated the gameplay so much that I never even tried to play New Vegas (which I bought at the same time.) Granted, I don't like any Bethesda game. I've bought several of them, trying to figure out what it is that makes them so popular, and I honestly don't get it.That's apparently hotly debatable. I think the downward trend for the IP began with FO4, though cracks were showing even during the Black Isle/Interplay days. FO3 had "aggressively mediocre" main & side stories & quests and characters for the most part compared to Interplay/Black Isle's Fallouts and New Vegas, but was fun and interesting regardless. BGS excels (or used to) at creating interesting worlds to explore. (Now, it's over-reliant on procedural generation, imo.)
I don't think BGS was ever all that great at story and characterization though it had its moments. New Vegas is a great example of a fruitful partnership. Obsidian wasn't at all experienced at creating open worlds to explore, but exceled at story and characterization. Each was complementary to the other back then. Were they to put their heads together on a Fallout game -- BGS handling map creation and possibly vignettes; Obsidian handling worldbuilding, story and characterization -- it could well turn out to be among the best RPGs of the entire series, imo. Not at all likely to happen, but there we are.
Open World RPGs (at least story-lite ones, I enjoyed Witcher 3 before I got bored with the open world stuff...I just can not ignore map markers, and clearing out level 3 bandit camps at level 20 isn't fun) just really aren't my thing, I guess.