Really don't think this is necessary. Like I get it you really like the character, but I really don't think we need power play to be an aspect of the relationships. Especially not Minthara who, whether you can or can't accept it, isn't an NPC that is going to keep up with us after we move on to Moonrise Towers.
Frankly I'd be happy to go back to the days of fading to black if it meant people wouldn't suggest this kind of stuff. I think as far as it should go is little things like making Astarion say "Please" before his one romance scene. I think it imparts a feeling of realness to things and is a kind of funny thing to do to him. Though if the devs give into one thing it will just be one after another. Fanfiction is the avenue for this kind of stuff, not a AAA CRPG.