Lyn,
For the Amarr Empire specifically, I think for me it's more to do with say, what's the differences between the Imperial Houses? They've existed for millenia in some cases so you'd think they'd have all developed very clear idiosyncrasies. Ardishapur has the most evident right now since it has things like the silver hands, furriers, and staunch conservatism at least to work with and build upon - but what of the others? There's also Khanid, but I'm not sure what's really unique or different about Kor-Azor, Kador, Tash-Murkon or Sarum beyond some superficial points.
That, and you'd think the Empire would be full of things like Imperial Court intrigues or feudal holders having disagreements and trying to shaft each other using the law and their personal networks of friends and associates in the bureaucracy or whatever. I mean, for a science fiction feudal society the Empire seems not to suffer from actual internal feuds at present, and the same can be said for all the factions.
Then again, the times CCP has presented unexpected disagreement within a faction there appears to be cries of outrage about it.