It probably depends on the time frame of your film, and the number of characters. If you're dealing with a dozen people over the course of two or three days, not only isn't the audience going to be able to focus on any one character enough to notice a change but there probably wouldn't be much to change. At best, an aspect of their personality others hadn't seen might come out. On the other hand, if you're dealing with a small cast over a few months then if the events of the movie aren't changing the characters in some way there's no reason to be making a movie about those events

Both Tim Burton's first Batman and both of Nolan's are interesting case studies as well.   

In Burton's Batman, Michael Keaton is already Batman at the beginning of the movie, and he's still Batman at the end.    No arc there.  But Nicholson's Joker has a complete arc - we see him become the Joker, we see him BE the Joker, and we follow his story all the way to its end.

In Batman Begins, we see.. well, Batman begin.  So Bruce Wayne gets a full character arc in that one.    But in The Dark Knight, he's the same throughout.  Sure, he suffers a lot and becomes a pariah at the end, but these are just things that happen to him, they don't actually change his character at all.   

Ledger's Joker has no arc either, he also stays the same through the entire movie.    Of all the main characters in TDK, Harvey Dent is the only one with an arc, albeit a tragic one.

It's the same dynamic as the classic Western anti-hero like Shane, or the Road Warrior, or Yojimbo... the title character doesn't change - he just shows up, does his thing, and then moves on.   The arc-ing is carried by the supporting characters.