The same thing people love about Morant is what equates to him not being that great of a leader. You can have fun and all but a level of seriousness is needed to elevate to that next level. To be fair, I don't watch them much but when I do, I don't see him calming the grizzlies when they're lacking composure.
But other than that, he hasn't really grown much as a player or managed to stay healthy. I know people are inclined to blame everyone else but those 1st couple seasons or so the grizzlies won a ton of games without him, even in the playoffs. They even have a winning record without him this year.
They have talent, they just need to put it together. Players need to continue developing, leadership need to improve. They need to find a good coaching fit to get the best out of what they have.