I agree, they should be raised. Remember when they used to be 250 Cr XD Oh God that was awful.
As per weekly challenges, they should not be things like "Beat this mission with these things", I like the ones where it's like "Play this playlist this many times" or "Achieve this many kills in this playlist", not "Beat this on Legendary in less that 12 minutes"
Really? A weekly challenge should NOT take less than 12 minutes. It should take DAYS as it is a WEEKLY challenge.