John/Rodney is the ultimate despite pairing for me- despite their differences and their respective drama, they still get each other, y'know? But D/s AUs in general (though I can think of an exception or two) are because stories; John and Rodney are together because one of them is a top and the other one's a sub.
So, what I really want to see is them getting together despite both being tops (I guess they could be a sub/sub couple just as easily, but sub!Rodney still sort of gives me fits). Maybe John can't deal with subs because of his tragic past. Maybe Rodney can't deal with subs because he hasn't got any home training and doesn't know how to respect them. But they still get each other, and maybe they can make it work despite not being the world's greatest and most perfect match.
Maybe they have crazy, furniture breaking, incredibly combative sex that people can hear in the next corridor. We all know John's kind of a sadist; maybe Rodney's a masochist- then John could tie him up and beat him red while Rodney called him a little bitch for not doing it hard enough. Maybe they have to fight the man, because no one will recognize their relationship like they would if one of them collared the other.
Or maybe they're bi, y'know? Maybe they've collared someone- IDK, let's say Katie Brown, for sake of pronouns (and cause that would be super hot)- and they put their heads together and make terribly devious plans concerning all the exciting stuff they can do to her. And then, when they've got her all trussed up in some complicated predicament and Rodney's making her squirm, John's so turned on watching that he can't keep his hands off him, to the point where Rodney has to stop what he's doing and say, "Do you mind? I'm trying to top, here."
You could even have conduit porn! Maybe they start off trying to share a sub, but they're so wrapped up in each other that the sub's like, "Screw this, I'm out, you guys seriously just need to do it and get it over with."
I just want to see some variety, y'know?
Now, time to go finish my Big Bang. ::headdesk::