What if we changed his ult? From a tank main, it's extremely underwhelming compared to naut, poppy, ornn or amumu. It just kind of, exists?
Natures Grasp: Removed
Fury of the Forest: new
First cast: Maokai roots himself in place and sends thorny brambles surging out in all directions, rooting+damaging champions they come into contact with, revealing and marking them as caught for the root duration. I'm thinking this will travel at the speed off Ornns ultimate (not sure which one though, as ornns second cast is faster than the first. But maybe too fast for this.)
Second cast: Maokai brings his branches to a halt and hauls all "caught" enemies towards him. Stopping halfway between Maokai and the point at which they were caught (this animation will be super quick, so like blitzcrank quick. Not urgot quick). If it wasn't clear, second cast stops the ult in it's tracks (so no more people will be rooted after this)
Damage: unchanged so 100/200/300. Will deal no damage on second cast.
Range: I'm thinking 2/3 of an Ornn ultimate