Styling is subjective, but I will comment on the roots. The idea behind a root over rock bonsai is that it should look like the tree grew on the rock, and its roots extended downward into the soil. For this reason, a tree is typically grown on a rock, rather than planted on top of one after its root structure is set. In your composition, the roots do not appear to grasp the stone. They just sit on it. I would recommend you ditch the rock, bury the roots, and lean into the bunjin style you seem to be trying to create. Nebari is not essential to the bunjin style.