If I was another team, I would want Melton. He played some good defense for a rookie. You can always use that off the bench.
Personally I feel like Okobo has the potential to be a good scorer. Half his problem is just not knowing how to use the skills he already possesses. His ball handling is very good, he has pretty good athleticism and speed, he just hasn't learned how to maximize it yet. But he is a pretty bad distributor - and that generally does not get dramatically better.
Melton may become a decent shooter, but he lacks Okobo's fluidity. He could become a pretty good 3 & D player though.
Remember though a big factor is the contracts each are signed for - okobo has 3 more years at a low rate whereas Melton is only contract for 1 more season.
It seems to me most of the team liked Ellie wheras Melton is not hanging out in the valley boyz. This is another factor.
I think taking everything into consideration, I would probably trade Melton.