I mean, I'm of the belief that there can't be any character development unless you let bad things happen to your character. If people were just handed things "because" and didn't undergo any kind of turmoil or pain or doubt in some way, there would be no character development, and without character development, you can't have plot (at least not a good one).
Assault's fine just so long as 1.) it's necessary, 2.) it serves as some kind of development to the character, and 3.) it's not overdone for the sake of shock value.
Last House on the Left is a movie that I enjoy, but I mostly enjoy it for its high stakes. There isn't really any sort of character development as a result of the main character's trauma though (she's beaten, kidnapped, raped, shot, etc.) and it mostly just serves as an "I TOLD YOU SO" victory for the mom, who's sort of protective from the start.
A better example of good character development through trauma would be The Call, where Halle Berry plays as a 911 operator. She undergoes her own trauma when she witnesses the death of a young girl at the hands of a kidnapper/murderer. This plays into her development later, when another girl is kidnapped by the same guy and she has to be the one to help the girl while also trying to track her down (but the whole subplot to her development is that she has to try and get over her fears and self-doubt from her past trauma with the first kidnap victim; by the end of the film, she's redeemed her herself TO herself, by basically atoning for her past mistakes by helping the second kidnapping victim and putting an end to the kidnapper's plot).
TL ; DR don't be afraid to put your characters through a bit of hell, just make sure that it incorporates into their development somehow and isn't just a random one-off. Build up to it in some way, and give it a proper send off. And of course, make sure it fits within the entirety of the story. Don't pull a Loss lol