So,
How much of the actions of Scott, Emma, Namor, Peter, and Illyana be blamed on the corruptive influence of the Phoenix? How much is really their fault? They didn't ask for the power. Tony causes them to have it.
They were asking for the power beforehand. It's just they thought only Hope could harness it. They were all ready to use that power to empower Mutant-kind before they ever had it. So yeah, it's their faults, in my eyes. But this is comic books, eventually things will go back to the status quo. Cyclops in particular is just too iconic to stay away or villain forever.