The reasons why peharps nobody complains about Malphite

I am not saying that Malphite is weak or that he isn't stronger than Riven/Zed/Lee Sin/Yasuo (the champions that tend to be complained about a lot and I will use as example) but maybe those are the reasons why nobody complains about Malphite:

1. When Malphite kills you, you will always know that's because he can out-trade you since he is an armor stacking tank. In addition, Malphite has high damage WHEN compared to other tanks. His damage is still obviously inferior to an assassin's burst.

2. Malphite does not have tons of mobility. His only mobility is tied to his ult. And it is an important engage tool so Malphite can't just use it as a dash.

3. He has way less snowball potential than champions like Yasuo, Riven, Lee Sin, and Zed.

4. You always know that you can't kill Malphite because he will be stacking armor. On other hand, you never know when you can kill a Zed or Yasuo or Riven because they can outplay you, even if they are low on health.

5. Since Malphite will be stacking armor, you know that it's obvious that you need to build armor penetration. But against Zed for example, items that can counter him are not as obvious counterbuild options (Zhonya, QSS). In addition, most AD assassins/bruisers not only can affort to build early armor penetration, but they SHOULD built armor penetration because that's how they mainly increase their damage. However, a mage almost never can afford to rush Zhonya against Zed.

6. Speaking of which, Malphite's main form of counterplay are rather obvious. Don't try to 1x1 him if you are AD (because of his armor, attack speed reduction, passive, etc); Stay separated and scattered (so that Malphite can't hit all of you with his ult). On other hand, Yasuo and Zed's main form of counterplay are not as obvious; Play safe (they have a very strong early game and all-in potential at early levels), dodge their abilities (Yasuo's and Zed's Q) focus on farming instead of poking them (because they can dodge most mage's skillshots, so trying to poke them is risky if you don't have point-click abilities) wait for them to waste their escapes or overextend before calling for ganks.

7. Malphite is considered to be less fun to play by most players. As such, he is not as popular and you don't see him nearly as much. And due to that, you don't tend to have as many frustrating experiences involving Malphite than involving Riven, Zed, Lee Sin, Yasuo, etc.

8. If Malphite is low on health and you have kill potential on him, you can always kill him unless he wastes his ult. You can't do the same against Riven, Zed, Yasuo, and Lee Sin, because even if they are low on health they can just escape (Riven has tons of low cooldown dashes, Lee Sin can just kick you and/or ward jump, Zed can use his shadows, Yasuo has his windwall and can dash using your minions)

9. When Malphite wastes his ult to escape, then you get happy because you know that you couldn't kill him but Malphite lost a very important ability and can't initiate/engage for a couple of seconds. However, Riven/Zed/Yasuo/Lee Sin's escapes are tied to their basic abilities, which have low cooldowns, so they don't have to worry about wasting a precious ability.

10. Not only Malphite uses mana, but he has very high mana costs. He can't poke you a lot on the early game with his Q, for example, he will become OOM if he does that. On other hand, Riven and Yasuo are completely resourceless, while Lee and Zed use energy. All of them can potentially stay in a lane for much more time than Malphite. Because of this, it feels much less frustrating to play against Malphite early game than to play against Riven/Zed/Yasuo/Lee Sin early game.