I’ll accept that the art style is not to your liking, but a comparison to Liefeld is unfair, Miller absolutely can draw feet. 
But seriously. Miller was always capable of doing standard superhero comic book art, DKR and Sin City were very much a progression of his artwork and even though I at one time did view that evolution as a devolution, I’ve come to appreciate how he was able to create such a striking original style.
It’s sort of like, and stay with me here because I am absolutely not comparing him to Picasso, but just like the following examples of different periods of Picasso’s work, we can see Millers arr progress through the years.
My point is that the drawings in DKR are a choice, he could have drawn it using a more conventional art style, but he deliberately went with something much more striking which I think paid off, you can disagree of course but he absolutely is capable of doing much prettier artwork, unlike Liefeld.
Different periods in Pablo Picasso’s work:
Now, since he is still very much alive, I’ll say that I lost interest in his work some time ago because of his extreme views, but DKR is still some of the best comics I’ve ever read.
Edit: A word.
