Funny enough, Jordan mentioned this in today's interview. So I wonder if it'll go deeper than just physically aging since they know it's an easy out with healing powers and resurrection.
"It’s clear that when he uses these powers, it drains on him. That said, some of the powers that he uses are healing factor powers. So that probably can dampen that sometimes as well. And he shaves his head and beard regularly. So you don’t actually get to see what color his hair is most of the time, but I think if he continues to use his power in that way, it will be something that he has to reckon with. And, of course, when told only do it in life or death — with the X-Men, it’s always life or death. So I don’t know that he can stop. If there’s something he can do, it sounds like he will. So this will probably continue to be an issue for him. But who knows how much of an issue, because we have resurrection. Maybe it’ll all be OK."