Increasing TTK is just a first step...

First of all lets address this. Increasing TTK is improvement for sure, but it is far away from fixing fundamental issues League has today. Lets break this problem into points so its easier to understand.

1. LCS : Since start of season 5, Riot has been pulling a lot of resources to make LCS much more appealing to watch for wide audience. Including people who have either no idea how the game is played or have never even watched LCS. I really believe Riot tried to make League into next generic sport like football. They have been dumbing down mechanics so people who have no clue can still predict outcomes of with just information on screen.

1.1 Global gold buffs : There have been global gold gain buffs so strategies that were confusing to people who do not understand value of gold did not feel left out. "Why did they lane swap, why is jungler farming all the time, why is first turret so important, why is drake kill so significant". Those are questions Riot wanted to avoid so they buffed gold globally to the point where your gold advantage becomes pointless by the time of teamfights. People who understood value of gold lead were more capable of predicting outcome of fights than people who did not.

1.2 Global experience buffs : Back in season 4, there was no mechanic called catch up experience. This meant that lanes that were behind would stay behind. Solo laners would achieve higher levels than any other lanes. This mechanic on itself was not that confusing but it opened space for strategies like power farming hard carries. Best players were left on lanes alone only accompanied by junglers when they were threatened by enemies. This gave the game more diversity and space to shine for individual players. People who used to cheer for popular mid laners and top laners are not watching LCS anymore because their favorite player can no longer shine. They are all kinda same. Riven used to be really popular pick among highly skilled proffessional top lane players, because Riven was capable of solo carrying the game and people loved it. Now every top laner plays the same. Pick the beefiest top laner from your pool and farm for while until teamfight phase starts. No more unstoppable Huni that has to be shut down by several players at once. Just a boring tank player that is going to do same thing enemy tanks is going to do. Engage, faceroll, hope for the best.

1.3 Jungle pathing and farming : Back in season 4, jungle camps had much higher spawn rate but much lower gold value. This meant that farming jungle was legitimate source of gold and if you picked champion dedicated to farming jungle camps, you could outfarm and outlevel solo laners. Jungling used to be very difficult role, not only you had to take care of your lanes, you also had to do it with proper jungle pathing. If you did not path properly, you loose jungle gold and if you fail your gank, you lost precious time. Jungle used to be hardest role from game experience and strategy point. This also brought diversity in picks and strategy. This however was not very friendly towards inexperienced watchers. "Why would Shyvana farm for 20 minutes. Why is she so strong with 0 kills". Again an example of unwanted questions by inexperienced watchers. So they nerfed jungle respawn and buffed gold income. You do not need to plan your path anymore. This also puts more pressure on lanes. Previously you could predict where and when will jungler gank just by knowing the path they choose. Game knowledge everyone had to know if they wanted to succeed. Now you only know for certain that jungler will gank top by 2:15 mark. If he does not, you are in dark. You can no longer plan your lane. Freeze minions so you can crash into tower. Because you never know when is enemy jungler going to randomly pop up and kill you 1v2. Because of that, lane duels became rarity. Something viewers cheered for a lot. Bjergsen solo outplaying enemy mid? Crowd was vile. Now he plays utility mages and farms until teamfights happen.

1.4 Shortening the game times : LCS is played as best of 3 or best of 5. LCS games are significantly longer than any solo que game because of the stakes. Noone wants to loose the game with 1 mistake. This made LCS rather exhausting to watch. If games went even and end result was 3:2 a single LCS match would take around 3 hours. This would wear out both viewers and players. Riot decided to shorten the game then. Nerfed tower health and armor, increased damage across the boards, catch up experience and global gold buffs also helped in this significantly. The end result is rather sad. Solo que game times went down by around 15-17 minutes, while LCS game times did not change much. Reason? Increased damage across the boards made every champion capable of oneshotting any champion. Single mistake would loose you a game a lot more than before. So LCS meta became even more stagnant and boring. As result, LCS viewer ship dropped to 50% of what it used to be during old meta with long game times. Because with such short TTK most champions lost individuality and most pro players lost their signature picks. Everyone plays same thing. Everyone is scared to do anything. Noone enjoys that anymore.

2. Champions : I do not have that much to say about champions themselves, I really like new champions and reworks, good job riot but :

2.1 Meta champions : In current state, in every elo there are 5 top picks for every role, that are basically must pick/ban. Around 10 are playable, and rest is totally unviable. This changes based on patch but never improves. If something is too op it gets gutted and if something is too weak it gets over buffed. Endless cycle of top picks and thrash picks. Maining a single champion no longer is viable strategy. You cant put 120 hours into one champion and carry yourself into any rank you want. Because sooner or later, either Riot will buff your coutner to the point where he is picked all the time, or they will just randomly nerf your pick and you have to start over. It is much easier and viable to just play flavor of the month. Less time required with much better results. Players loose individuality. You can no longer be proud Riven main, because she is either so broken that noone will like you or she is so garbage that noone will be impressed.

2.2 Individuality of champions : This is closely related to TTK and shortening the game times. In this game there are around 130 champions so obviously you will find similarities. However most champions now play the same. One shot or be oneshot. I used to play Darius a lot. I am talking 350 games in 2 months just Darius. I got to the point where I was capable of consistently beating 1v3 fights in my elo. I achieved this thanks to huge healing output and smart bleed stacking. Darius was embodiment of bruiser. If you fight him for too long, you will get rekt. This has changed. Darius now is palyed with Tri force, trying to pick off the squishiest target and one shotting them with ult so you can apply bleeds with your passive instantly. Instead of unstoppable juggernaut he was, he plays more like assassin that trades all of his mobility for powerful ultimate. And thats how you play almost all top laners. Garen, triforce. Riven with lethality. No more outplaying. No more wearing your opponents down. Just kill or be killed. This issue plagues mid lane as well. Jungle is occupied predominately by burst champions. No more power farming Shyvanas. No other strategy exists. 130 champions feels more like 20.

3. Rewards and blue essence : BE has been single worst mistake Riot could have done to this game in my opinion. Yes lootboxes with random free skin shards are fun and offer you free content for mere price of your soul, but BE is fundamentally toxic to this game. You used to get IP based on amount of time you have spent in the game and outcome of the game. Every time you played, even normal game, you felt that you achieved something. When you saw that 120 IP even from loss, you felt like "Shit that was worth it". No more. Yes, you get more experience for winning than loosing and more exp for playing longer games. however, rewards are random. You could play 40 minute games 8 times in row, and get Fiddlesticks champion shard. That is completely worthless. Random rewards for doing something consistently are making people unsatisfied with them. You start feeling like there is no point in trying. You are either gona get that Annie shard or Darius shard. Doesnt matter if you try for it or not. And this is comming from someone who is currently sitting on 135k BE and all champions unlocked. I could have at least see my IP rise steadily. No more. Also increasing experience required for level upping further is really predatory mechanic that has only one purpose and that is to squeze your hard earned money from you. If this game is casual, why am I not allowed to buy champion pack for 60 euro and get all champions for ever. If this game is esports oriented, why are not champions unlocked in first place. It feels like Riot decided to grab the worst from both worlds and combine it into abomination the rewards system is. Just try to guess how much would it cost you in dollars to unlock all champions in the current roster. More than 700 dollars. And if you buy your champion, how do you know that it will be relevant in 2 weeks. This game is not either esports friendly or consumer friendly.