Finally? I feel like a broken record but we have seen Jean without the Phoenix many times and each time lasted many years. This is nothing new. I don't know why we act like it is a new thing. Naturally Jean existed before Claremont turned her into the Phoenix. Jean was sans Phoenix during X-factor which was like 1986-1991 and Jean didn't even get the Phoenix codename until 1994. She was still without the Phoenix force proper during the entire 90's. Jean became fully Phoenix in Morrison's run in the early 2000s (at the end of his run as most of his run she was just channeling it). Jean didn't have the Phoenix when she appeared as Teen Jean (she was what Teen Jean about 8 years our time?) She didn't have it during X-men Red. Jean without the Phoenix has been done. We know what the character is capable of without the Phoenix because we have literally decades of story showing us what she can do.
I do concede and agree that writers got way carried away with the Phoenix and it might be too outlandish and OP (however Jean is an omega mutant so she's OP by definition - at least her telepathy could be).
I liked how Jean was defined in Morrison's run as a grown up omega mutant. She had the power and potential there and still had flare ups of the Phoenix. It was the best version of Jean (in my opinion), and as much as I love X-men Red, to me Morrison's Jean is still the best by far. She had the best of both worlds (omega level mutant psychic and she had her phoenix connection).