You think Joe Johnson is better than Melo?
Yes. At this stage he is. Melo was always a primary shotmaker at his core. Once he lost that first step completely, his drop from star #1 option, 6th man to 14th and 15th man on a bad roster who provides vet leadership for the youngins, the right mindset to get better each day, it's a grind, and adjusting mentalities and how to deal with adversity is really close to each other depending on what you provide.
Since Melo isn't much of a leader, mentor or worker, he can't be C. So he must be A or B. But he can't be A because he fell off and he can't be B because his offensive is no longer efficient and he can't switch well or defend in space as a 4 at this stage due to father time.
Melo just doesn't have a diverse skill-set. Now if we are playing pickup or 1 on 1. Melo by that standard would still be in the NBA. But that's not what the NBA is. It's a role locked league. You gotta find your place and fit your role. The reason why teams want Joe is he proved his lateral quickness isn't bad to what it was before his last season in Utah and athletically, he is healthy again. He shows 9th to 10th man value now. That's a 12-15 mpg specialist who can score, defend and provide intangibles that can help you in spades, especially in the playoffs. He isn't just better than Melo for the NBA right now. He is vastly superior in the role based league that we have today