Each week/month, all of the challenges look the exact same as the previous weeks. Campaign is always “Complete Level A with Skulls 1, 2 and 3 on”. Spartan Ops is always “Kill XX Jackals, XX Crawlers and XX Elites” or some variation with enemies, and the Monthly Challenge is ALWAYS “Win X amount of Games in War Games”.
Is it impossible to have more variety? Halo Reach had dozens of different challenges, and it didn’t just repeat over and over.