Dick Grayson's suit recently got a major upgrade, as his civilian life and adventures as the suit grants Nightwing limited immunity to gunfire - an ability that will vastly help the stories DC can tell with the character. Given the heavy presence of guns in comic books, it makes sense that bulletproof armor would be a necessity in any hero's costume design, but this idea tends to be handled inconsistantly, if not outright ignored.
Comics writers usually avoid having their heroes get shot unless it's a core focus of the story, but that decision often conflicts with the idea of taking on organized crime. The gap is filled in different ways: hardened criminals will somehow only have access to bats and crowbars, or have Stormtrooper-level aim, or the hero may even break the limits of their powers to stay alive (see Gambit's recent super speed.) Sometimes, these explanations are thrilling, and the idea of a hero expertly managing the major threats in a group can help to communicate their expertise, but as characters like Batman and Black Panther have gradually started wearing bulletproof armor as standard - and with even an archetypal street hero like Nightwing ing in - it's time to make bulletproof costumes the norm.
Nightwing's new suit protects him from small-arms fire and even stabbing, but with the suggestion that it remains vulnerable to more serious weaponry and superpowers. The thin costume likely means that bullets will still pack a punch, striking the perfect balance where Nightwing's usual skills and acrobatics will be needed to stay ahead of his opponents, but the comic doesn't need to stretch believability to stop Blüdhaven's gangsters, villains, and corrupt cops from opening fire. This makes Nightwing's abilities more believable and immersive to the reader. Now when he takes out a room full of armed hostiles, the comic won't need to bend reality in cliched ways to make it possible (at least not beyond the sci-fi costume and gadgets which are already a given in superhero stories.) Given the way in which Nightwing has pulled off this change, it makes sense to consider making this concept standard for other street-level heroes.
The subtle level of realism added by bulletproof armor makes comics more enjoyable to read, because it ever so slightly raises the stakes. Every reader already knows that their favorite hero is highly unlikely to get fatally shot by a random goon, if only for narrative reasons. A Nightwing-style costume makes this official, but it also makes gunfire a more present threat by stripping away the hero's plot armor. This means fights can be as frenetic as possible. In the event that a character does lose their bulletproof armor, or it breaks, then the story or situation just becomes that much more thrilling (in the same way as when a hero loses their actual superpowers.)
Introducing the idea that the average superhero suit is ingly bulletproof would be ideal for characters like Green Arrow (currently running the Justice League) and Robin (a super-skilled assassin who just concluded a death tournament.) These characters are already way beyond worrying about regular goons, so making this official would only excuse writers from finding excuses as to why no-one ever manages to shoot these non-powered heroes. Marvel's heroes could benefit too - heroes like X-Men's Cyclops and Guardians of the Galaxy's Star-Lord could technically always be taken down by a single shot, even though they won't be - and the existence of unstable molecules in that universe could make the bulletproof suit standard overnight with one tweak.
The new, upgraded suit donned by Nightwing has a functionality that swaps an awkward problem for comic writers and turns it into something cool. What's more, it doesn't make Dick feel overpowered or unrealistic. Writers should consider making this small Nightwing detail standard for experienced street-level heroes, as this subtle concession is a better option than the bag of tricks currently used to keep heroes out of the line of fire.
