Why porn though? You might have Durandal imply that he's why Clef lets out a shotgun round every time sliding doors unexpectedly open or close . Maybe some remarks to Bright on the closure of the universe. Incidentally, how is Clef still around in the 2200s?
The few random phrases are not the "entirely different speech pattern". They are phrases which belong to said speech pattern, which I contend is inconsistent with Durandal's as portrayed in the terminals of the Marathon trilogy. They do not belong in his vocabulary, this is not how he _talks_. Go and see for yourself.
Basically, I'm worried that you've Flanderized Durandal into "all flamboyant mockery, all the time". And without regards for Durandal not having a human viewpoint.(e.g. "seven times table" being more familiar to an AI than "right arm")
I'm not sure where I was going with the self-promotion thing. I think I was trying to show that he wasn't quite that egotistical, or at least that he did not display his ego in the way you are portraying him as doing.
I do know that the whole "gimme a D/U/etc." happened while he was still in the throes of rampancy. You may want to check whether he pulls anything like that in the later games.