It's hard to take a bunch of bald, hunch-backed trolls as serious enemies. The Cardassians became a much better adversary for the Federation. Are they good guys? Are they bad guys? They were both at different times! And they were always serious.
If the Ferengi were going to be retained, I'd say the cannibalistic aspect hinted at in "EaF" should've been kept as a serious element of their culture. If they're going to be creepy and ugly, at least make something
about them scary!