Originally Posted by Obazu

It's an interesting idea, but i think you could mix it up bit more that just making the target different heights.
For example have one move back and forth, another moving up and down, maybe place one of them behind an obstacle, make one have a weak point at a small area so that you need to be precice with your hits to get it, make one bounce back up when it falls and one hang from a ceiling so that you have to do a high jump kick to get it.
Those were just some things I could think from the top of my head. Go nuts with it.