As I think more on it, I feel that DnD shouldn't really have roles - because if there are roles, those roles need to be filled. And most players I've played with, especially new players, aren't interested in playing whatever the party happens to need. They want to play a character they've made, who fits the narrative tropes they're drawn to, and play that character through a story. Battles are part of the story, but the battles should serve the story, not the other way around. Not even combat as sport; combat as performance. They want to do their cool thing.
Put another way - most people I play with don't want to think about party composition before making their character. They already know what they want to play, or will randomize. That means the game works best when it works with any mix of classes, from the classic four to all artificers. So each pc needs to be flexible enough to fill all the roles until you get into the nitty-gritty.
Ergo, it's quite alright for fighters to be tank-dps-support-control-healers, emphasizing different aspects based on build. Making all fighters tanks will tick off more players than the few who get confused as to what they should do, especially when "attack with your weapon" is always a solid choice.