i personally have a 57% win rate on him as a maokai main this season... and with close to 700 games on him total since season 5 i have an over all win rate of right at 58%
i started with him top in season 5 and have worked him mid, jungle and support. cant figure out how to make adc maokai work though...
his damage is lowered that is a fact... he is 4 cc abilities which is great for any team comp . i would agree however with the ult change there more of a clear picture of skilled maokai vs a non skilled then before.
this season i play him top,jng, support havent had a chance to play him mid yet.. might start doing it vs kat as i did before and wrecked.
one of the biggest things that is a lil unnoticed cuz it happen so long ago is the splash/impact damage on E when before you could use it to last hit and cs from range based on that impact damage... which made even bad lanes reasonable for him. now with that gone ( has been for a while) its clearly harder to lane vs bad match ups.
i have always played him as an ap bruiser type except support where i currently play him as a what i like to call " the shielding tree "
that way i can legit tank/peel cc and engage for team while still protecting the carry i need to with the face/locekt and knights vow