There probably won't be as much at stake as with Spider-Man. In the case of the Fantastic Four, Reed Richards in 616 is already about 50, Susan Storm is in her 40s, same with Ben Grimm, while Johnny Storm is just a little older than 616 Peter. Dr. Strange is also about 50. So aging them is more about bringing them to their deathbeds than anything. In the case of the Fantastic Four it's about Franklin and Valeria becoming the future leaders of the four, while Reed and Sue play with their grandkids.
In the case of the X-Men, Cyclops is in his 30s, pushing 40. Wolverine is an immortal so with him it's more healing factor: wax on/off. An Old Man Thor is already being touched in Jason Aaron's great run on the character.
The issue of Spider-Man aging always did have more teeth than any other character since it's inherent to the engine of the character. This is a guy who has aged and grown up significantly more than any other contemporary superhero in a running serial superhero story. So it's only natural to speculate what later adventures would be like with this guy.
I'd say the main stories were: Coming Home (with Peter teaching high school, fighting Morlun) which also incidentally happens to be a favorite of Zdarsky's. There's also Back in Black (though I am pretty sure Kingpin is dead), and of course "To Have and to Hold" by Zdarsky's good friend Matt Fraction. I also think one or both of Peter's children will have powers, and maybe that red-head kid will become the Ultimate Spider-Man stand-in. Obviously the tragedy that awaits Peter in his final years would be the death of one (hopefully not both) of his children. And the idea that Peter's story begins and ends with the death of a Ben Parker (first his uncle, and then his son) is well, full circle in a horrible but entirely logical way.In the meantime, we should think about what we could expect from the remaining issues:
- 2000's: The main stories in this decade were "The Other", "Civil War" and "One More Day".
I think the 2000s is gonna have Peter and MJ and others lament America heading into Iraq like they did Vietnam much in the way many boomers went "Did we learn nothing from Vietnam?" when that entire thing happened. The answer is : Nope, no lessons learned.
I think Zdarsky will go with Spider-Men, because obviously Miles Morales is the biggest and most important new character in Spider-Man in those two decades.2010's: We had a lot of interesting stories here. We had "The Grim Hunt", "Spider Island", "Spider-Verse", "Dead No More" and some more. "Spider Island" could give us a reason for Peter to continue as mentor of new "Spider-Heroes", "Spider-Verse" should be left aside because we are focusing in one reality mainly, and "Dead No More" could have some interesting prequels.