See, the Bethesda name, for me, is synonymous with absolute quality! Yeah, Oblivion was their poorest effort , but the fact that was still an awesome game shows just how strong they are.
Still, I understand where you are coming from, there are plenty of games and series out there that I dislike that lots of people like.
I have the exact same problem with Rockstar. I liked Vice City, but that aside I've never even slightly enjoyed any of the games they've published.
And it's not some kind of arbitrary nonconformism, it's just I really think they're massively overrated. Nothing wrong with digging either publisher, and their respective franchises, but the way the critics foam over them is just disproportionate and excessive in my honest opinion.
Bioware are the western RPG masters for me, and pretty much every sandbox game I've ever played I've really enjoyed and have preferred to GTA. So it's not that I dislike the genres of these games.
The common criticism I have with both is that their games are quite boring, both gameplay and story-wise. My other criticism of Bethesda -- an obvious one; their dated and buggy engine. This especially gets on my nerves, as any game without the behemothic label of Bethesda or Rockstar would be critically mauled for being so buggy, and yet the Fallout games* -- and Red Dead Redemption too -- were buggy but critically praised. I'm a firm believer that games should be finished when they're released, and not sold too early with a "we can patch it later" attitude.
Obviously opinions are opinions, but I'm just quite bemused as to how I can be in the vast minority with these ones. I keep thinking I'm missing something when I play RDR, GTA, Oblivion, Fallout and so on. Why did everyone else love them? Ah well, to each their own.
*admittedly New Vegas did take a bit of a critical hit with the buggyness, but the point's still valid.