I love all missions that Riot make , but rewards for that missions are very boring .......
I am here to suggest something new !
If you complete mission , you get some Orange Essence ( OE ) .
You can use OE to unlock skin shard in Loot , or you can use it to buy RP .
Eg. 1. You complete mission
2. you get 200 - 300 OE
3. You can unlock skin shard in loot / you can buy RP ( 100 OE > 35 RP )