The quality of those games (and this one) has nothing to do with Bethesda. Publisher doesn't mean crap.
Well, technically most publishers ARE in fact the cause for bad games. Be it quality control, pushing release dates, forcing developers to implement and/or work on projects that don't interest them, restricting development budget for marketing and so on. They do in fact have a role in the development process but not in Dishonored's case (at least not so much).
They wanted the studio to make a game that Arkane personally likes and they gave them
a lot of creative freedom. Although, the release date is still too early and I believe they pushed it in front of most anticipated games and the pre-order bonuses. While those things take about 2 or 3 hours to code for a one man job, they still take away from time working on the actual game.
As it stands Bethesda have made a ton of good moves and almost arbitrary bad ones to the point of non-relevance. The experience people will have with this game will be great, I can say that for certain.