Harder Weekly Challenges

I'd like to see harder weekly challenges for MP. I complete them all within 2 hours.

For comparison, the daily challenge for time played is 60 minutes, and for the weekly challenge its 90 minutes. It just doesn't make much sense.
I think a weekly challenge like, "Get 500 headshots" would be something reasonable. Or, "Get 50 double kills." You all get the point.

Sincerely,
IGotThatSack