I've been playing Imperator: Rome recently and I agree, the lack of monetary compensations surprised me. During ancient times they were a major aspect of truces and peace treaties, perhaps even more than later ages. For example, we know with accurate detail the money requested for the first punic war, various hellenistic wars, even the interactions with many warring tribes: why cannot I impose an exorbitating amount of talents to be paid by Carthage after I vanquished it utterly? (which might in turn increase corruption inside my borders)
I really wish for a small update that adds them. Maybe along with some more sophisticated requests such as "do not expand in this area", kill someone, or exchange of characters. We might request young heirs to a leading position as temporary captives and potentially groomed into future allies (or backstabbers), or princesses for my family members.