Sync is no where near as important as the file corruption. I refuse to play Multiplayer until this bullshit is fixed. I mean, I should be able to play the game without fear of losing all my progress. Order of Problems:

1.Profile Corruption (Has to be fixed as soon as possible, or I will be probably not buying another CoD title.

2.Lag Shooting (Very annoying that a whole clip can't seem to kill somebody when I point them.

3.Matchmaking (Shouldn't have to wait longer than I play.)

4.Hosting Issues (I find that when I host, my cursor is prone to darting all over the screen, plus the lag.)

5.Controller Tuning (Sorry, the above take preference.

I also played some MWR last night and it was a shock to discover lag shooting all over again. I quickly got used to it as it was the only way to play for me as I hardly ever got host in that game. But i'm not looking forward to lag shooting in core mode. Its probably a good thing that the game isn't yet released here in the UK so when I eventually get on, my clan friends will already have unlocked the HC modes and I can just jump straight in their games.