Thanks for the replies so far, good stuff to think about.

What about both of us playing the same class for all 5 characters ... like 5 shammies?

Is the awesome power of 5 shammies due mainly to the coordination by one player or could they be even better if controlled by 2 players who learn to work very tightly with each other?

Neither of us have shammies, so we would begin at level 1 and find out if we can make it happen.