Shen seems to be in a half decent spot right now -he could use a lovetap
If I was going to try to buff him into a full way decent spot I think all I would do is give Q an AD ratio instead of AP. I know "BUT MAH AP SHEN" but I really think he'd function better if he could get a smidgeon of scaling off of hydra not to mention have some chance at dueling and winning instead of just dueling and trying to shrug off dmg through sustain and shielding.