I wonder... would the game improve if the backdrop sprite just returned and didn't scale or render... could be an easy patch?
https://www.youtube.com/watch?v=d4r_4TFUzLE
I suspect it would play faster, I'm not sure if it would be better though. It was a rubbish arcade game as it was, and really only stood out because of the fancy graphics effects. None of which were ever going to translate well to 8-bif machines (or the 16-bit machines tbh).
Without the background it would just look like a very dull beat em up, I suspect.
Try the Sega Master System version if you want to see Pit Fighter with all the scaling effects removed. It is a very dull beat em up, and somehow even more sad.