Originally Posted by
Harpsikord
Teen Jean proved to Marvel that everyone saying that there was worth in Jean Grey as a character wasn't lying. She held not one, but two team books on her own, had a successful solo run, and yeah. She's the entire reason that adult Jean came back.
Now, in-story there hasn't been much done with teen Jean and the consequences from her on adult Jean yet. That'll change - eventually. As soon as there's a writer that wants to do something with that, whether that's the pink form, Jean using telekinetic weapons, or referencing interactions with other characters.