Maybe it's just me, but I always have trouble figuring out what apps are by reading the documentation. I'd usually understand more if there was an architecture diagram, which also clues me in that I need to do one for Vespene :)
One other reason I didn't build something is I don't have a current need to use something like that, so I'm probably not the one that should be developing it. There's a lot of datacenter use cases I'm ultimately not super familiar with.