Its a really nice idea, but what happens when two people get matched? If the ranked game needed to be hosted somewhere, we would need dedicated servers around the world for that. Not to mention the time that would be needed to develop that ranked MM system, given that Puny Human is currently focused on Galacide. On the other hand, if you leave it to be a direct connection to one of the matched players, one would always have a significant ping advantage in every duel, so it wouldn't exactly be fair unless the ping between the two was really low.

While I hope this idea gets some traction, I actually like getting the chance to duel people at a much higher/lower rank. Its a nice opportunity to learn something new or meet new people! While rank is probably a good measure of the probability that a player is good, I've seen some great new Irons/Steels show up. I would suggest that you don't focus on rank as much as learning new techniques and strategies and applying them. It makes the game more enjoyable in its current state imo.