Melandri is talented, just a bit of an attitude problem.
He caught fire at the second half of his last WSBK season and I think he would have won the championship if he had gelled with the Aprilia earlier on in the season. He probably would have been a contender for the 2015 title if Aprilia hadn't pulled him off to go to MotoGP.
His lack of performance in MotoGP was in retaliation for being yanked from WSBK. He just didn't try. Just like when he was on the Desmosedici with Stoner in 2008/2009. He just stopped trying after realizing he couldn't gel with the bike (him and every other rider who tried). It's not possible to finish last on the order when your team mate is winning races. Not with his level of talent.
There's rumours that he may be on a pay-per-performance program with Ducati. If that's the case, it'll solve the attitude/motivation problem that's probably prevented him from landing a gig in 2016.
I know lots of riders starting out pay their own way for a spot on the grid. However, a rider of his calibre opting to be a mercenary instead of taking a salary is a dangerous precedent to set for the rest of the riders in the field. Especially on a factory team.
It's not going to make him very popular in the paddock.