Looks like a very clean and elegant approach to this year's challenge. I like the simplicity of the design, no complicated parts to break. There is something to be said about simplicity, I have seen many a team try to over reach their bounds and end up building a pretty crappy machine. I have seen some very simple machines perform stunningly. I have a feeling this will be one of those machines, not much to go wrong. Get it built and get practicing with it.
Best of luck, I really want to see some pictures of this robot unloading. I hope it is as effective as I think it will be.