> We’re all equal, so write software accordingly!
This is a good point. Any node in a robust network (healthy society) has the capacity to lead should a current lead node fail or simply have exhausted it's alloted time in the leadership position (e.g. for fair-sharing of energy or maintenance resources). This network simply needs to be structured to support a dynamic shift in power. However, even distributed systems typically use some degree of heirarchy to improve efficiency (1). Just look at the Borg Queen herself (2).
So, you probably will always need some term to refer to the striations in nodal roles, even if those roles are very temporarily assigned (i.e. the mobility of nodes accross those striations is fluid).
FWIW, I don't find "master/slave" any more or less offensive than "Little/Big Endian".
1. https://www.google.com/url?sa=t&source=web&rct=j&url=http://...
2. http://memory-alpha.wikia.com/wiki/Borg_Queen