Ascension
I think Riot should bring back ascension as a gametype indefinitely. I had a lot of fun playing ascension and I was really disappointed when I found out it was only for a short duration for the new patch and champion Azir. Ascension was the most fun time I've had on LoL chaotic teamfights all the time and killing for points and capturing relics as a team. This is such a fast paced gametype and it lets you play a whole new way that you don't get to play in summoners rift and twisted treeline. I would play LoL everyday for at least 3-4 hours a day playing ascension again. It brings a whole new dynamic to the game when there is constant team fights at the relics and trying to get the ascension power up and then trying to protect the ascended to get more points from the kill bonus and extra power. I really hope others feel the same and Riot can either bring it back or come out with something similar.