Divine Might will be nice for the Beastmaster and potentially the Warlord when they focus on playing and supporting creatures rather than attacking things directly. Mage Staff is pretty standard equipment, but the option to get your powerful creature you were supporting anyway to deal with incorporeal targets will be extremely helpful against mages that focus on those cards. There aren't that many yet, but they can already be somewhat problematic if you don't have a good card to deal with them. There are plenty of attack spells with ethereal, but I like to have a longer term solution both in case the attack spell doesn't kill the incorporeal target, and in case my opponent plays another incorporeal card that I want to destroy.
The Wizard, Priestess, and Forcemaster have easy enough access to ethereal attacks that Divine Might probably won't matter to them. It's more expensive to include in a Warlock build, so it's less likely to make the cut, particularly since most Warlock's will wade into combat, so Mage Staff is a cheaper solution to include in their spell book.
