I think this has two big things working against it. It's intended to be a comedy, and the guys have pointed out that riffing comedies too often boils down to variations on "That's not funny."
Ironically, while reading that review I could think of things to riff in the plot....
Amazing how this guy with no obvious income (if he has a job, he can abandon it for months at a time?) can afford all this stuff in the movie - the spa, the bribe for "Cole", etc. Yet he doesn't have money to fix his car or get a new guitar?
How they just happen to run into a hot dentist/male model who has to give away (we think) thousands of dollars of free dental work just to get laid? And that, despite her dental problems she never ever went to a dentist before then? ("You'd think someone would have called Child Protective Services.")
Or a dermatologist? Or a pediatrist for that toenail? ("See why we need single-payer healthcare?")
In fact, how about the overwhelming question of why didn't she ever try any of these things before now? Or why didn't Hilton's character try to get her this help before? How could it be lack of money when they live on the beach in Malibu?
Besides, just think of all the Freddie Prinze, Jr./"Pretty In Pink"/"Breakfast Club", etc riffs.
Jeez, I'm talking myself into this.