Rename A Domain Or Re-direct Email?

The animation school I work for is going to change names soon. The website already reflects the name change. The CEO wants all current emails changed to fall in with the proposed change as well as changing the school domain. Currently the system works fine as it is and I am of the opinion that changing the internal domain name space will have no effect whatsoever on people outside of the organisation. If there is no need to change things, then possibly re-directing emails internally would mean minimum fuss to daily operations within the school. Has anybody found themselves in a similar position and what was the outcome?