I think everything on maokai is extremely slow now. They even added extra animation to his q and e which they didn't need.
Everything about maokai now seems slow af and that's not why people would play him. They would play him because his abilities flow nicely together.
The sad part is, they didn't change the flow. They overemphasized his abilities so much that it just FEELS worse to use.
Also, I think his e bonus damage and new ult are gimmicky as hell and having so much of his power in those abilities makes him feel like shit.
His passive is worse, and the improved heal provided I don't think will make up for how much harder it is to get now, but that is less of an issue.
Overall I think maokai was hard nerfed in this rework, not without reason, but nerfed nonetheless to a point where I expect him to be pretty weak, though not garbage, on release.