I actually didn't think the dialogue was that clunky (although I can see what you mean in certain scenes), it's more that there were quite a bit of typos, missing commas and things like that.
Overall, I actually think that the content of the dialogue flowed pretty well. Sure, it felt slightly forced every now and then, but never to the point where it became a distraction. And most importantly (to me, at least), the scenes never lingered too long. Pacing is the hardest thing to perfect - and many otherwise amazing AVNs still suffer from it - but this game has done that really well so far.