Don't get me wrong, I am a huge fan of Wolfie and I use him in most of my teams. Even I think this new update made him too powerful. My suggestion would be to halve the amount that he heals while in the shield BUT make sure that he takes NO damage while the shield is active. This is the best of both worlds before and after the nerf/repower.
The biggest problem with the previous wolfie was that his ulti was pretty useless because he took more daamge than he healed. Now he heals back to full health every time he uses the shield. Using my method, he won't be immortal but he also won't be useless.