Since season 4, there are almost no summoner spells in League of Legends that have a bigger impact than Teleport. Sure, Flash is a big deal and can change a team fight, but Teleport determines everything from which objectives you can take, to whether or not you can fight, to where each individual player can and should be standing on the map.
In fact, until patch 8.23, even just starting a Teleport then cancelling it could be enough to turn a fight, or save your team’s bot lane. But, after this most recent preseason patch, Teleport can no longer be cancelled. And that’s probably a good thing.
Now, when you want to impact the map with a teleport, you have to be absolutely sure it’s a good idea. No more faking teleports to get enemy teams to back off of a fight, or to bait teleport out of your opponent, if you start a teleport in season 9, you’re teleporting.
This is the kind of change that, rather than making one playstyle weaker, actually impacts the entire game itself. At the highest levels of the game, map movements will have to be more purposeful, while things like tower dives can be done with a little more confidence, knowing that the enemy team will have to either decide not to help the target of the dive, or commit everything to help them.
As for how this change might interact with some of the other changes made during the preseason, it’s still a little too early to know for sure. But, as the preseason moves on and we get closer and closer to the start of season nine, there are sure to be a couple more game changing adjustments.