Well, comparing P&F to the other Disney cartoons, it is indeed formulaic.
Case in point, Lilo&Stitch.
They had a formula too (experiment activates, Stitch chases experiment, Experiment gets their new home).
But they made every episode original, because they kept finding ways to do it differently.
However, since I've only seen 1.5 episodes of P&F, I can't say definitely what it is like.
Truth be told, given the problems with obtaining official dvds or iTunes videos of my favourite shows, I was getting rather jaded at that point and said, okay, I'm going to start limiting myself and only be interested in the very best shows.
P&F just didn't reach the bar to be counted as one of those.
There's no shame in that, many shows don't have my seal of approval, I'm quite discerning when it comes to declaring a show as "one of my favorites".
And I don't believe shows aimed at the young suffer from this problem, witness the infinite number of CSI whatevers.
I laughed when I read a comic set 100 years in the future and they had a tv channel that was composed of nothing but CSI shows, one for every city in America.
Yes, Frozone and Sally (NBC) don't appear to do much, but if you really analyse it, they do have major impact on the events.
For example, if Frozone wasn't there, Mirage wouldn't have located Mr Incredible (she found him by following Frozone around) and therefore, the movie would have played out completely differently, given that Mr Incredible wouldn't have gone to Syndrome's Island and they'd have never had a chance to practice using their powers before fighting the final Omnidroid.
As for Sally, she's trying to prevent Jack from making his colossal mistake (she has a premonition that shows her Jack's plan is doomed) and then she tries her best to fix his mistakes when she can't dissuade him.
Zero is just a gag joke, he doesn't do much in the movie.
Claus plays a minimal part, we only see him very briefly and his interaction with the characters is pretty minimal at best.
The Mayor etc are just secondary characters.
Even the Mayor says he doesn't know how to run the town without Jack.
The major characters in Cars are Lightning, Sally, Mater, Finn McMissile and Holley.
Sally was the driving force in reforming Lightning from a selfish jerk into a nice guy, assisted partially by Mater.
In the second movie, Finn and Holley are driving the story, since it's mostly about them and Mater trying to defeat the villains. Oddly, Lightning's presence is minimalized in this movie, even though it's all about him.