I wasn't into comics at the time so I could be off base, but I suspect a perception of Lorna and Jean as essentially "same character but different colors" may have been considered a feature rather than a bug back then. The first thing that comes to mind is Mortal Kombat. 90s had a tendency with stuff like that to simply change the colors, maybe one or two slightly different moves, and there you go, two different characters that 99% of the time behaved the exact same way.
Of course, most fiction since then has evolved from the 90s to give characters more depth. Kitana, Mileena and Jade in Mortal Kombat aren't simply the same design with different colors. Visually, their designs are distinct and fit their personalities and histories. Story-wise, Kitana has the regal and diplomatic warrior vibe (with fighting her mother recently built on), Mileena has being more of a cruel iron-fisted ruler of Outworld who wants to pick up Shao Kahn's mantle (she's no longer just trying to be Kitana), and Jade's been a royal bodyguard getting closer to the Kotal Kahn side of things. But it's also not like they have absolutely nothing in common anymore. Mileena was still made off Kitana. Jade's still Kitana's close ally and long-time friend.
Lesson learned, characters need to be distinctive from each other for engaging stories these days, and this even applies to characters that truly did have their origins as palette swaps with minor tweaks to what they can do.
I think what we've seen of X-Men #1 is promising so far in terms of their costumes. They have similarities and differences. I would vastly prefer Lorna wearing a modernized version of her iconic costume, but as I've said, I'm okay with this given Lorna's placement and awareness of her. I can't say anything about depictions yet because I think we need to see more; previews look promising for Lorna, need to see more of Jean.