Appears games like Assassin's Creed and Call Of Duty 4: Modern Warfare (2nd week) are greatly outselling Mario Galaxy's launch in Europe (well at least based on UK and Irish data where it was ranked 8th). I thought Mario Galaxy would top the charts, despite I don't prefer using a Wii-mote for this kind of game and don't like the upside down platforming on micro worlds myself. The Japanese launch was below expectations as well with Dynasty Warriors 6 for the PS3 selling 30K more at launch than Mario Galaxy did.
Maybe a Wii Sports 2 or releasing a Deluxe version may be a better option for Nintendo.