They are buffing Warwick on PBE

no he isn't, read the changes again

Q and W are much worse early game (the time where he is overtuned) and better late (the time where he's not)

Not sure how you see these as buffs unless you only looked at the max rank changes.

This overall is a nerf. The W change alone is a pretty huge nerf for his early game while the Q damage and heal change means he won't be max health when he ganks at level 3 anymore.

The small buffs for late game still do not change the fact he is still going to remain irrelevant after 25 minutes unless he is far ahead.