Jean is more than just her powers and focusing solely on what she is or was rather than who she is speaks to a lack of understanding of the character. What sets her apart from some of the other dual psionics is her passion. Jean has an overwhelming joy for life and a respect for it that very few others have. She's seen the good and the bad and she embraces both but she isn't tainted by any of it. She feels things in huge ways, she has big thoughts and bigger dreams and she sees setbacks a momentary hurdles, she doesn't give up. What she can't finesse she smashes to make a way toward her desires. She sees the good in people and she's willing to forgive those that have wronged her, hell, she'd die for some of them. She cares more about other people than her own life, sometimes to a fault but that's who she is. She loves her friends and would do anything for them, even if it's going to hurt her in the end. She's temperamental, aggressive, haughty at times and has a self-deprecating sense of humor and all of these things are what makes Jean who she is.
Thank god that she's more than just her powers because she'd be a really boring character to read about. Thank god she's more than just the Phoenix because writers don't know what the hell to do with her when she goes cosmic and one amazing story shouldn't be all that defines her for the rest of her existence on the printed page. Writers come and go and every single character has had a writer not get them, it's not just Jean.
I like Jean not because of whatever costume she's wearing or not because she's a cosmic flame goddess or even because she can stop a plane mid-flight. I like Jean because she gives her all every single time and every single time she's thinking about keeping her friends and loved ones safe, making sure the world is safe and feeling every single thing so damn deeply it would drive a normal person insane and she gets up every day to do it all over again and barely bats an eye. She's strong and it's not her powers that make her that way.
I feel bad for you if you can't see or understand that she's more than her abilities and power/feats isn't, nor has ever been what defines Jean Grey.