This was one of the things I mentioned in the feedback I sent to Larian. I found the narration far too sultry and smug, as you say, but smugness is something that seems to be at the core of a lot of Larian’s writing and is evident in the tone of most of the companions. Thinking on it more, sex seems to have received quite a bit of attention in this game according to the sex cinematics...I wouldn’t know because I don’t play CRPGs for the romances.
It’s not the most important part of the game, granted, but a narrator with a little more gravitas and wisdom in their voice would not have gone amiss but this is a personal preference of course.