He needed to improve his stamina and foot speed, but you could already see it last year when he filled in during the season. His scoring ability is ELITE for a big man, something we have never really seen here.
Now that I watch him with Love on the court? I don't see any reason he couldn't put up 20 ppg easily in his career. His midrange game is improving and his defense will get there. At some point, he will be able to play with good footspeed and maintain his strength as well, probably after another year of a good workout regimen.
I don't know if he'll ever be Jokic, part of what makes Jokic is his incredible passing ability. I don't think Zizic will ever have that part of his game. But he's already, IMO, on his way to being a top 5 big man in the NBA, scoring wise. And lest we forget, he's also ultra efficient when talent is put around him. He finishes through contact, is a good FT shooter....he's got the talent to be an All-Star.