For my game:
Orions=unchanged except for some added custom models
Korgath=custom models only
Prime= misc....ferengi,tamarians,pakled,kazon,civilian vessels etc.
Beast=8472,legion,B5,monsters
Wyldefire=jemhadr,breen,sona
Syndicate=Borg,Andros
Tigerheart=cardassians
Camboro=Tholians,B'lorian
Variety is what keeps the game interesting, I don't want to see the same 5-or-so models for 8 cartels