Oh come on! Wallmasters are a peice of cake! Most of the time Navi warns you that there's wallmasters in the room you are in. Whenever she dosn't the best thing to do is turn up the volume a little or just keep watchin your shadow. After they come down they stay down for at least 10 seconds and thats more than enough time to kill em with one hit from the biggoron sword.
All that stuff is what makes wallmasters so bad