Missions and why I think they could be done better

I understand missions cannot grant players an overwhelming amount of rewards but hear me out, as somebody who goes through normal games as fast as me daily I see that after about 3 games all my missions are gone. Even if an event is going on usually the only worthwhile reward comes at the end of the cycle of missions, I would also like to add that when missions were announced I figured they would be updated weekly or maybe even daily with new rewards and maybe even some super difficult challenges. XP and blue essence is ok I just wish more missions came and more reward variety was available. Not even just talking about hextech oriented rewards, perhaps there could be some really cool or funny missions you have to pull off that provide quite a challenge. Just sharing my thoughts thank you.