That's exactly it.
X-Men, and by extension, Fox, are lucky enough to have decades of fan favourites: well characterised, famous and much loved characters at their disposal. And even better, a strong element of diversity representation and incredible female characters arguably some of comics' finest.
So where the hell are they onscreen? Rogue is a breakout character waiting to happen. She's flawed, tragic, but strong, independent, fiesty, empowered... And fun.
I don't expect them to cut ties with the current continuity. It's far too early to be making those kind of decisions but after so long, perhaps starting over wouldn't be a bad thing. I don't think another period movie is going to be the breakout hit they need to take this franchise to the next level that it's so deeply, deeply capable of.