Runes Match History Feedback is great
I think it's really neat that on release we have feature to see if the rune setup made sense for the champ or not. For example I just played a game with Tahm Kench Support and wasn't sure if I should pick Guardian or Grasp of the Undying (it was an option last season) - and after the game I saw I shielded more than 1500 dmg.
For shielding and healing supports this is a nice feature to see if the numbers are okay or if we need to change our setup or improve our gameplay.