Shens sheild is much like ryze

You get it when you don't need it. The purpose of it before was to block some of the damage from skill shots. Now it is just there and stupid. Your not going to be able to get it when you need it. Also shen now has no healing sustain. As well as he fact that his old passive did damage and now shens only damage is from his q which scales from ability power (which shen doesn't use)

Here's my suggestion :

Passive: vorpal blade: every 3rd auto attack deals 5% shens max health damage and heals him for the same ammount over 4 seconds

Q: you can keep the new q

W: same as new one but. Any attacks dodged grant a small sheild relative to shens health for each attack dodged.

This might sound op but it has a really easy counterplay. Don't attack and they get no sheild. This at least let's shen sheild when he needs it rather than random.