Even if she only gets a year, a lot hinges on a) what happens with her during that year, and b) how others at Marvel behave around and after. Lorna on the new X-Men team shows a ton of promise, especially with the buzz generated around the vote, but it won't amount to anything if she doesn't have
both a depiction that works for her and support needed for it.
Popularity of Lorna through Gifted is a good example of what can happen in a year. The comic won't have as much chance to tell stories with her as a show does, but a powerful, impactful story that captures her complexity and history can be enough. Similarly, while Killing Joke was horrible for Batgirl and I'd urge people not to read it (and I say that as someone who actually did), it was powerful enough at capturing Joker's complexity and history to make an impression and launch Joker into a very iconic status for decades. Of course, it wasn't Killing Joke all by its lonesome that managed to pull it off for him. He needed support and usage beyond a single story too.
Though there's also another lesson to be learned with Killing Joke: overstaying nostalgia. It was good for its time for Joker. It was bad for Batgirl, and it's increasingly recognized as such with each passing year. Joker really doesn't need it anymore, and even if he did, it would require a major overhaul in its treatment of Batgirl. DC half-recognized this with the Killing Joke film... then failed as they decided the best way to "do better" was to throw in a relationship with Batman, as if making the emotional stakes higher for another male character somehow improved treatment of the female character who ends up getting shot and degraded. It sits at a 39% critic rating (out of 41 reviews) and 51% audience rating on
Rotten Tomatoes right now for a reason.