I feel like its a bit much to expect people to do the 20 weekly challenges and then be skilled enough/lucky enough to get the 5 Killing Sprees in Fiesta all in one week. Maybe if the Weekly ultimate was counting the killing sprees as u played in the background.
I get that i was able to get grind out the 20 weekly challenges in one day but for my friends with jobs and kids etc and who are bad at the game, it seems like an impossible task.