The entire episode takes place on the holodeck, in his program. I would call that the central focus. The moment he's introduced he basically becomes Guinan for the whole crew, and it does not make any sense. In His Way, yes, the focus is Odo and Kira, but their decision process revolves around advice from Vic, and that's what's obnoxious.
Even Worf goes to Vic when he's angry about his dead wife not getting into Stovo'kor. WORF. Bashir plays his music when everybody's preparing for a Gem'Hadar attack. Vic got forcefully shoved into episodes he had no business in, and that's what made him annoying.
Vic should have been a source of entertainment for the crew, not 1960s crooner Guinan.