I have no idea. It is pretty annoying. I don't think Treyarch cares much about the online gameplay for Wii. They have much more concern for the PS3 and 360 online services because they have (probably) something like five times as many players.
Basically as far as comparing yourself to others on the leaderboards you're kind of screwed for who knows how long, but you can still look at your own stats. The box still comes up with your rank, exp, kills, deaths, etc.
If you want to see your kill/death ratio, just divide your kills by your deaths.
Say your kills are: 17300
& your deaths are: 7420
Your KD ratio would be: 2.33
It's sad because last time the leaderboards were up, my k/d ratio was only 1.8 and it's already gone up to something like the equation I used as an example lmao It's definitely been over a week now.