I had no problems with Vic Fontaine per se, and Paper Moon was a big payoff for the casino narrative. However, the fact that it was a holodeck fantasy was unnerving. Even from the 1990s, it seemed like a dated premise, an idealized vision of an era that was just the veneer that covered corruption.
On the other hand, the casino was a symptom of the problem of much of Star Trek: the unwillingness to make downtime interesting, particularly to inject some romance. DS9 needed a nightclub where people could dress up, not a holographic program where they could play at being glamorous. Instead, social life on DS9 is little better than a futuristic mall: you hang out at the food court and shop at the boutiques. And the Starfleet people are so stolid: unless they are in costume for the purpose of the holodeck, they are always in uniform.