I feel a bit vindicated by this. I always said the same thing "Original Cast should have starred in Apocalypse" especially after the movie turned out so dissappointing. Original Cast would have saved us all the origin story shenanigans and actually given us seasoned X-Men going against their "biggest" threat yet.
I'm not against that kind of origin story at all, but if you're doing Apocalypse and selling him as their biggest foe, it is underwhelming. Especially when you're saying the Ancient Mutant rises in the present... in the 80's? meh.
I think there would have definitely been more hype for that cast going against him rather than newbies.