The 'love/hate' thing wouldn't be set in stone, it would be a preference. An example: you want CivA to join you in a war against CivB, but they tend to like CivB. So they require 50% more value in negotiations to agree to do it. If they hated them, they'd require 50% less. All these values would be trivial to add to the editor (change who likes/dislikes who, change how much that effects negotiations).
The reason I like this, and the the reason I liked it in SMAC, is that it gives context and personality to the game's diplomacy. The utterly lifeless and bland AI leaders we currently have mean nothing to me. I can't say I hate Elizabeth, or am afraid of Bismark, I just don't care. But ask any SMAC player how they feel about Yang or Miriam (assuming they don't play as them), and be prepared for a lengthy tirade. It's this kind of thing that makes a game a classic, something that leaves a lasting impression on you. Something that goes beyond just mere game mechanics and becomes personal.
