Power Without Gameplay
The problem here is that you are denying the game of so many game designs, just because people can't appreciate it. But why do you bother trying to make the players appreciate it? Because in the end, does it really matter? If the game is won by sacrificing money and time unto items that give lot of team-fight potential and thus the team focuses on team-fight potential while lacking in other areas, you bring more diverse angles to the game. If people do not appreciate the fact that they won the game because they stacked auras, then why did they buy them? If they do not buy them and the enemy team does, they lose team-fights in theory. And they will find why and they will see the items that gave them such edge in team-fights and they will LEARN to appreciate the items.
It comes down to the fact, how you want to treat players. Will you treat them like stubborn children or adults? Because I don't see a reason to force something to be satisfying to the player, there is no need to. Player is responsible for drawing entertainment and satisfaction from the game, you do not need to do it for them.
Burden of Knowledge
This one is a really funny, because due the context of LoL and DotA. The very foundation of the game demands burden of knowledge and learning by the heel. The game, the concept of the very genre of AoS demands it to be full of little things you need to learn to play it, because of the diversity it has. Over 60 different kinds of heroes, even over 100 in case of DotA, all work very same, yet very differently. All the items, all the quirks, all the jukes, all the tip and tricks that makes the AoS game, all of them have to be felt. AoS is one of those games where you have to learn by sweat and tears, it can't be undone. FPS games have it easy, you know everyone has a gun. Guns shoot bullets, they kill you. While the gun changes and how it dispenses bullets, the core concept is so easy to see there is no need to study the game. But nothing, pretty much nothing sticks to the concept in AoS games. Only things are the auto-attack and moving, everything else has to be learned what it does. In a fighting game you don't need to guess will that kick suddenly cause somekind of scripted status that will kill you in situation B under spell A. It hits you, BAM, you take damage.
And it gets worse every single patch of LoL. You bring more content, you make the problem worse and worse. Don't you think it is better to embrace this issue rather than avoid it? There is so much you could do with the game, at the expense of making it harder to get in. Or sorry, was this against the whole idea of LoL? Being the baby's first AoS game? Don't you think it is obvious why LoL has gained this title?
Isn't this just making spells simple for the sake of it being simple? Kunkka's ship has a pretty clear use to me. Use it to start a fight. It goes through your team, hits the enemy team, massive advantages for your team and massive disadvantages for the enemy team. Since it starts fairly back behind the real action, you can space your teammates far behind you and they still get the bonus. You know when the game is in its optimal use, when both the enemy gets hit AND your teammates get the buff. Requires little bit of skill and know-how to both aim it to the right spot and from the right angle, but that is why it is so powerful. The risk of failing is related to the prize of success. I don't see a reason to avoid making risky and multilayer abilities just because someone might be confused of them. Let them learn.
Fun Fails to Exceed Anti-Fun
Ah, I love this. Because here is where LoL starts to get confused because of the purpose it is supposed to do. You should know the basic fact that you can't ”make fun”. Fun is not matter, it is not something that is produced. Entertainment has to be created by the player, not by the developer. There is no way developer can guarantee fun, for you do not exactly know what people enjoy. By trying to guard the player of disappointment, of the feeling of failure, only in the long run makes the game too stale, too frigid. I take it this is why such as “early game heroes” or “late game heroes” don't really exist in LoL, so that someone doesn't feel cheated when they are outmatched early game due to hero picks. Or that some people feel late game heroes are unstoppable after not doing enough to hinder them. Goal of the game is to be a game. People play it and try to attain whatever their goal was for the game. Everyone has a different concept of what is fun and when you class things as “anti-fun” that should be avoided, you are locking lot of game mechanics out of the game.
It also bring another point. Mistakes are not fun. Are they anti-fun? Because then you could reason that we could balance the game around making variable “X” amount of mistakes. Heroes over perform when you do less than X mistakes and under perform when you do over X mistakes. Since mistakes are the norm rather than the exception, you compensate by making heroes that are riskier to play lot more powerful than they should be. And this causes lot of balance issues. Or should we do it the right way, the unfun way that heroes are presumed of doing no mistakes at all and balance around that, causing people to have “not fun” as they are not able to perform to the bar. One of the common issues that competitive games have to solve.
This one is just plain weird. It treats having multiple purposes as a negative property instead of positive, that it could/should be. If an ability can be used for multiple purposes, then good? It allows greater decision depth to the game than if the ability had only one singular purpose? Because the example is shoddy at best, since lot of damage makes a great initiation ability too. Stacking lot of burst quickly on someone is one of the basic ways to eliminate key players from the enemy team. It is just like the optimization issue, you can't be afraid of players having to cope with the fact that some things need to be learned. Experience will tell them where to use and when to use multipurpose abilities in varied situations. There is no need to avoid this!
Add risk to the game to avoid it becoming too safe. Risks that offer good awards push players into more exciting gameplay. Best way to see this is just look at Sona. Her design is extremely risk-free and has lead to really boring lane phases due to her nature. Do not be afraid of risks.