When playing this game analogue I often see people ask a player to attack a very specific territory more so than a specific player.
It's useful for traffic navigation when you're in an alliance so the person you're aligned with doesn't leave you with the option to A. Attack someone with a high number of armies or B. Attack them/ go through them to weaken someone else.
Also useful for pointing out areas that will weaken another army. Like taking one of the territories in the continent they hold.
Also asking to attack a specific spot while agreeing to attack it yourself. And going with the turncoat rating you could have a percentage shown that says how often you actually follow through with attacking the area after they did as well so people know how reliable you are.