If you don't like the slow movement in Granite, just skip granite. Stone Armor (even without granite) is going to be better than either shield or WP. Invul will also perform better. However, out of just those two options, Shield probably ekes out the win because you can have soft capped defense with higher resists than a WP soft cap build. You'll also have more DDR. However, willpower has a ton more regen available and also better endurance management.
What secondary are you looking at? For a "just want the best tank" secondary I'd recommend Dark Melee. The heal from Siphon Life will keep you topped off.
As for epic, I'd suggest Soul for Darkest Night. The to hit debuff won't be that important if you're soft capped, but the -damage will always be useful.