with two mages, i agree. you can easily switch leaders if you need to. the spec and button setups should be somewhat identical, at least for the major spells.

for things like frost nova, which should either be on round robin, or used with modifiers so the mages can take turns, those dont have to be identical macros. or maybe it should be!

focus system is easiest, and changing leaders will mean that you clear focus for the new leader and set a new focus for your old leader now slave.

and never use "exist" in your macro. 1) its exist without the S. and 2) harm or help already implies existence. i think they took it out too, as one of my macro had exist and i would get an error from wow saying that exist is not a known option.