I think it's best to level W over E for the first time ever. The shield only triggers more passive procs if it stays up, so leaving it at one point will result in it doing nothing.
Well, the verdict in Classic is that he's hilariously OP now
They said Volibear was OP on release over there, and he's dropped to **** tier now after very minor tweaks. I've been trying out Shen builds and I think his damage output is much better now. I've actually been building him like Derpwick, just with Randuin's instead of FH. It works better than trying to force that expensive Trinity in there.