Teleport needs a Rework. Here's how I would do it.
Those who have started following competitive League of Legends within the past two years might find this hard to believe, but there was once a time when not every top laner took teleport. The current teleport meta has its roots in a time where Twisted Fate and Shen were high priority solo lane picks. Opposing top laners were forced to adapt and take teleport and the competitive game hasn't looked back since. At the start, teleport was a boon for the competitive scene. It allowed for a wider range of compositions and enhanced a team's ability to make map plays throughout the game. No longer. The game has outgrown teleport in its current form. The meta game has grown predictable, stale. In the early game, Teleport serves as a get out of jail free card for poor rotations or for top laners to get back to their lane after double jungling through the 4-0 tower push. In the mid game and late game, teleport dictates how each team reacts to each other. When teleport is up, teams send their top laner to split push while they dance around an objective, if only because they think can't of anything more productive for that player to do. Split-pushing with teleport is almost always the best decision for a top laner when teleport is up. When teleport isn't up, the game stagnates as each team waits for it to come up to contest the next objective. A misused teleport can be a death knell for a team's chances of winning at this point in the game. A single summoner spell shouldn't have this much of an impact on the game, and that's why it shouldn't be a summoner spell. I'd like to replace the teleport summoner spell with a teleport consumable I like to call the “Teleport Totem”.
What is a Teleport Totem?
A Teleport Totem is a consumable that can be bought in the shop like any other and the teleport function would be the same as the teleport summoner spell. It would be single use, and there would not be a cooldown. While you wouldn't be able to have more than one at a time, you could theoretically buy it as frequently as you want. Instead of gating teleport by time, it would be gated by cost. Each time any player on your team buys the Totem, the cost would increase for everyone. The starting cost and how the cost would increase would depend on how Riot wished to balance the item.
One possibility is to have the Totem cost 25 gold, and have the cost double each time it is purchased (25, 50, 100, 200, 400, 800). The first few uses would be relatively inexpensive, making it comparatively accessible to Teleport in its current form. The cost would start to become prohibitive with the sixth teleport, with the 7th teleport costing 1600 gold and only being a viable purchase in the most dire of circumstances.
Another is to have the Totem cost 0 or 100 gold and increase by 100 gold each time it is purchased. This would put a stronger gate on the item in the early game, while keeping the Totem more accessible for a longer period of time. A cost of 100 gold would eliminate the ability to have teleport at level one without sacrificing early game power. This would force more meaningful decisions in the early game and reduce the ability for teams to use it to cover up for poor decision-making.
Why a Consumable?
Part of the reason Teleport makes the game so predictable is that it has a set cooldown that teams can time and play around and teams know which player is going to use it. And if your top laner can't fight the opposing top laner, then it becomes a wasted summoner spell and you're forced to choose between taking a risky fight while the enemy takes your base, or defending against the split push, hoping your top laner doesn't die and possibly losing your base anyway. With teleport as a consumable, a team could change which player they have use it throughout the game. A lot of popular top laners in the past year haven't been great split pushers. Rumble and Lissandra don't have much threat since they can't kill towers that fast. But imagine a team having their ADC split push while they objective dance. It'd be a big risk, since they wouldn't have their primary damage dealer at the start of the fight and teleport is best used for flanking and you don't want your ADC on the other side of the enemy team alone. But their presence as a split pusher would create a huge threat and require teams to force action quickly. In short, the ability for any player on the team to have it makes the game less binary.
*Note: I would recommend a separate slot for the Teleport Totem so it could still be used in 6 item scenarios. Or have the totem always be there, but have the consumable give the totem a charge that can be used.
Why not a Summoner?
This question may seem redundant to the one above, but let me explain. As long as teleport exists as a summoner, top laners will have to take it. It's just too valuable to a team's macro strategy. Apart from those top laners that take smite (what a time to be alive), flash is also mandatory. This has pushed out a number of all in, lane bully style champions that would ideally take ignite from the meta. Removing teleport as a summoner would allow these Champions back into the meta and likely cause a massive shakeup in current tank meta. Right now, we have predominantly tanks in 3 roles and that's, frankly, boring. Ignite would increase all-in potential and not having to take teleport would greatly expand the pool of viable top champions.
Why no cool down?
The average time of game is up significantly as teams often wait for fifth dragon as a win condition. Neither Dragon or Baron are in healthy spots. Dragon scales poorly, with each Dragon after the first one having little value beyond being needed to get to the fifth one, while Baron is arguably too strong and has forced teams to build compositions that work well with the benefits it gives you. But that is a topic for another day. Having teleport have a cooldown makes it too predictable and has had an indirect effect on team compositions. Compositions that want to snowball through the early game and end by 25 minutes aren't really a thing anymore. Instead, teams predominantly play strong late game compositions that are heavy on tanks and if the team happens to get a lead, the game is all but done for if you don't scale as well. Removing the cooldown eliminates the predictability. Teams could build compositions that all in on the early game and use the ability to teleport frequently to make plays all over the map. The scaling cost would make this risky, since you'd eventually be unable to teleport, but that would be the tradeoff you'd make for the ability to make more early game map plays. Of course, a team could also choose to not use teleport at all in the early game, and save it for some grand all in gambit with 3-4 players in the late game.