Something tells me he wasn't really referring to the sound quality of the film's dialogue.
There are criticisms you can throw at Blade Runner. I'd probably disagree with them, but in some cases I'd see where you were coming from. Labeling it "dated" seems fairly strange, though, given that it is essentially the opposite.
Blade Runner was clearly ahead of its time given the marked influence it ended up having on things even outside of the sci-fi realm, and it is also one of those movies that received a mixed reaction upon release but ended up being viewed as a classic of the genre later on in retrospect.
If you're going to call it dated because it visualized an LA with flying cars in 2019, you should be prepared to take almost all sci-fi to task for similar things.