New Runes: Too Many Minigames
Many of the new runes make me feel like I'm trying to complete side-quests or minigames in order to maximize their value. The 3-unique-hit mechanic for Electrocute and Phase Run is understandable from a design perspective, but it heavily influences the way I try to play or the runes I want to pick now as abilities like Cassiopeia's fangs or Garen's spin don't proc them alone. Grasp's new health-stack is cool, but it makes me feel more pressure to proc it as often as possible. Weaving in auto attacks is usually a part of gameplay anyway, but now I feel obligated if I take Kleptomancy.
All of these keystones on top of things like trying to decide which minions are best to dematerialize for this game/champion, desperately trying to stay in range of minions deaths to maximize Overgrowth's potential, cast my ultimate on cooldown to grab that 15% bonus CDR, sweep every bush in the game to collect every eyeball I can, and dodge/avoid/understand/figure out all of the things the enemy has or is trying to do as well.
I do understand these are just first impressions, and the learning curve is steep for everyone, but thus far I fall heavily to either side of ignoring new runes completely, or focusing more on them than I am the game I'm playing.