If I remember correctly, Jean wasn’t a favorite for Morrison or Taylor, but both wrote her perfectly. They understood her and they knew her voice. Percy seems to be going in the right direction, at least I hope so.
Hickman writes Jean as she was written in the 60s. Maybe he is going somewhere with that, I don’t know, but in the meantime he is doing her a great disservice. And it really doesn’t matter if there are story reasons behind her portrayal, you just don’t piss on what previous writers have done with a character. Maybe there is a power-up coming in the near future for Jean, but if you want to write interesting stories about a female character in 2020, this is not the way to go. Claremont gave Jean her character development in the late 70s, let’s build from what he did, instead of regressing Jean back to Marvel Girl-Jean in order to re-tell Claremont’s more than 40 year old story.