Rammus is a very interesting champion. He's a small little bugger that can go pretty fast when he wants to, while also being a durable tank that's hard to burst down. Especially after the durability update here his shell got a little bit stronger once more.
With his lack of voice lines and his unique look, he is a well-known champion to anyone and everyone that plays League of Legends, and yet he remains one of the least picked junglers in the game. Let's take a look at Rammus and why we barely encounter him on Summoner's Rift.
One Dimensional Playstyle
Rammus is a fast moving tank, something we don't really have much of in League of Legends. With his Q, Powerball, Rammus can zoom from lane to lane, looking for single targets to literally destroy.
All you need is a few items like Thornmail and you'll be hitting like a truck. Thanks to his passive, Spiked Shell, Rammus' basic attacks deal bonus magic damage equal to a portion of his total armor. When using his W, Defensive Ball Curl, these stats are increased by 50%. This also applies to enemies that land basic attacks on Rammus.
- Rammus on the big screen... now isn't that something to behold, eh?
The end result? Your opponents take more damage than they can deal out. This means any squishy ADC will be completely and utterly afraid of Rammus. But... that's about all he can do really it's very one dimensional and you'll be going for the same plays over-and-over again without my variance.
Rammus is Easy to Counter
Rammus might be one of the fastest champions in the game, but that doesn't mean he's unstoppable. Sure, he'll be rolling straight for you at 200 miles per hour, but with a single champion that can interrupt you, you'll be crash landing back on Summoner's Rift with nothing to show for your efforts.
Ahead of Patch 7.10, Rammus was always curled up when in Powerball stance. In Season 7 though, Riot gave the champion a slight rework where they made his Q a channel spell, which means any type of attack that can stop a channel will be able to put a stop to Rammus' fun.
You don't even need to have a crowd control ability to stop Rammus from charging at you after the changes in 7.10. Something like Viktor's Chaos Storm is able to stop Rammus from going crazy on the rift. This means that he's actually a very simple champion to counter.
Rammus' Dependence on Armor
Rammus can have some busted armor numbers thanks to his aforementioned abilities. He will be able to deal more damage the more armor he's stacked thanks to his abilities, which is different from most other tank carries who do not have their damage so closely intertwined with the amounts of armor they've stacked.
This dependence on armor makes him extremely susceptible to armor shredding items and abilities which could make him completley and utterly obsolete in the game. For example, Black Cleaver or Jarvan IV's Q are easy ways to counter Rammus.
If you cast your Defensive Ball Curl as Rammus ahead of the enemies armor shredding abilities you'll end up with no armor, no damage. Basically, Rammus becomes nothing more than a glorified minion at that point. Hell, even minions will have better stats than Rammus.
Another reason why Rammus is seldom picked is how unreliable his damage is. As already mentioned, he's highly dependent on building armor, meaning that if he decides to build some health items like Warmog's he'll lose out on a lot of potential DPS.
This means he's extremely reliant on items to deal as much damage as he can, but you also cannot build specific situational items like Warmog's in case the enemy Jinx decides to go for Kraken Slayer. So, even if you want to be a strong fighting tank, with such numbers, Rammus is going to have a hard time consistently dealing damage since it's so easy to counter him.
Rammus is a fun champion, he's quirky and different from a lot of other tanks, but he is a very situational pick and therefore, many don't bother to play him. Sure, Riot tried to fix some issues with a mini rework last year, but it hasn't helped him become more popular yet.