Here's what I would like to see:
Upon opening the zones page, it would have a button to scan for other running MC's. It would search the network and then offer a checkbox type window where you could check computers you want to add as zones. Then, offer auto naming conventions such as IP address, computer name, MC library name, or random sequence numbers (1,2,3,4).
Then, you could play things to each zone independently or all at the same time with something to keep it in sync! I have always wanted a way to play music over my other computers (which I have got) but with an added sync method that would keep everything in very close sync. You would think with a big pipe such as 100Mb ethernet there would be no delays at all and it shouldn't have any trouble keeping sync.