My suggestion for a second Olaf rework:
Passive: Same as before
Q - Initial slow greatly increased, following Q's against the same champion deal greater amounts of damage but have a reduced slow amount to prevent permaslowing.
W - Reverted to pre rework Olaf's W.
E - Damage increased, cooldown decreased, scaling removed, HP costs are now flat.
R - Passively increases Olaf's health by a % based on his maximum HP.
Active: Renders Olaf immune to all crowd control effects, and causes every autoattack during this time period to stun the target for 0.1 / 0.2 / 0.3 seconds.