Intriguing idea, I like it. But like Djarid mentions, it would have to be done in a separate addon. As to limitations. There would be spam, but unless you'd go waving your mouse around in Shattrath primetime, I don't see a problem. I would think the addon channel should easily be able to handle every mouseover event, when damage meters and similar addons can stay synchronized in raids. The question is will it be fast enough?

Peej: Not through regular macros. Theres software to allow for mouse cursor to be centered onscreen for example, but it wouldn't be very practical for blizzard, flamestrike etc.

An idea for Keyclone maybe? Broadcasting mousecursor position to cloned windows. Tied together with a Blizzard macro, I could see that working.