The redo key-bind addon only works for things you have painted and bricks you have placed, it doesn't work for things that have been duplicated nor does it work for anything hammered, wanded, nor /clearbrick'd. I agree, it would be useful to increase the redo addon to allow for the redoing of hammered, wanded, and /clearbrick'd bricks, but with an RTB pref limiting the number of bricks redo, or one that allows a large section of bricks to be redone in parts, every 5,000 bricks or so.