I get that you prefer the more conversational style of diplomacy like SMAC did.
One issue is transparency. The reason RT puts the numbers in front of us, is to help the player see why the AI is reacting in a certain way. Conversation and negotiation is fine if the player knows something about the AI personality, otherwise the AI comes across as schizo like it does in civ5.
And I would argue that diplomacy is also about relationships. So making special agreements with another side and seeing your respect rise and your relationship improves to cooperation is diplomacy too. And that is what RT's simulates really well.