The Sepulcher's Savior shield looks like a lot of fun. The on-use swapping its ability is a little odd, but still fun. Personally I think the way to go is "start DPS, immediately blast for snap threat, then have the shield ready for later use". Both passive abilities also look handy for Mythics where we're more likely to be surrounded and beaten.
Anyone else look this guy up yet? What do you think of the general idea (numbers can be tuned)?