At this point in his career, I don't think Hayward will "lead" a team to a championship. But I do believe he can be a helluva player averaging 18/5/4 and a threat from 3-pt range. But he is NOT a PG and shouldn't essentially be used as such. Let Hayward play to his strengths. That is entirely the fault of the coaching staff and FO.
We would look foolish for trading him for less value IF/WHEN he goes to a team that uses him correctly.
IMO Hayward is best served to start and be a secondary ball handler and scorer with a starting unit. By staggering the rotations to let him take the lead against other teams backups. That would maximize his value. What that would be salary wise is hard to say.
This role for hayward requires him to be the 3rd option. Ideally with a big time post threat and another perimeter scorer.