As long as they're visible one way or another, I guess. But I think the Halo 2 approach would be the best bet. Show the current playlist rank next to the player's name, and show their highest rank on their player card/highlighted name.
I'm just worried. Every game since Halo 2 where they've messed with the ranking system they've made it worse.
I agree with this. I suspect we'll see the ranks in the player profile, maybe the playlist rank, maybe the highes rank, who knows.