"So, what would happen if I put it on Bonewall?"
2 more defense, so if a creature had 2 or less attack, it wouldnt remove a counter.
"Gravity Shield's ability would become extremely out of place."
creautres with under 5 hp would have to deal with the 2 block.
"Flooding?"
missed that one, ill think of something.
"Wings would work the same as Dim. Shield?"
no, airborne creatures (who are able to get past wings otherwise) would have their attack reduced by 2.