Teleport Cancelling
Usually, I'm okay with most changes that Riot makes. This isn't one of them. This is, personally, one of the worst decisions gameplay-wise that Riot has recently made. It seems small, but can be a big thing.
First of all, I see nothing wrong with League having more mind-games, outplaying, etc. You said that players should mind-game with higher commitment? Then just make it so that cancelling it doesn't reduce it's CD. Second of all, do you bloody know how awful this is for people who missclick Teleport in lane? Because that just happened to me, and is the biggest reason why I'm making this. I was playing Irelia top. Now, I usually play her mid for fun, with Ignite, but this time, since I'm top, decided on Teleport. I was against a Rengar. And guess what happened. We fought and, whaddaya know, I accidentally pressed TP, thinking I had Ignite with her. And the worst part is that I couldn't cancel it. At all. So he just kept basic attacking me until I died. Which resulted in me, not only giving him early advantage (he had Dark Harvest btw, so he can scale well), but I had no bloody TP, and it was on full CD. Which lead to me giving him huuuge advantage, thus making him snowball out of control whole damn game, and lost us the game. And the funniest part is, if I was able to cancel it, I'd kill him. But since I couldn't, I died. And that lead to the midlaner flaming me (and we all know Riot doesn't like toxicity), which lead to me feeling far worse than I did. So please, Riot, revert this bloody change. It's one of the most aggravating changes you have made so far, without a doubt. (plus, it makes people think that you don't want mindgames, and are against smart play)