It would be nice to have an option to associate different compression levels with either hosts, groups, or images. That way if/when you are needing to image a system that has crap for processing performance you can associate it with a lower compression level, allowing it to finish the task more quickly at the cost of disk space on the storage node. Yes, you can currently adjust the system wide compression level, but this effects every task running (that uses the compression obviously).
I am not sure on the feasibility of this, and ideally this wouldn’t be a long term issue since we should all be throwing systems with Atom (and similar) processors down a flight of stairs.