It is a re-balancing, not a buff. He will be worse at roaming now that his knockup is less powerful (and presumably with a higher cooldown at low levels. The changes will make him more dependent on getting some farm and not being a no-item tank. He will have to leech from lanes longer for some farm.
The changes were to make Drain less powerful in the lane early on, but keep his jungle similar. The dark wind change should also make him a better jungler.