The "tank meta" doesn't exist
As much as that line is going to get me downvoted by people who won't bother to read what I'm about to say.
The tank meta doesn't exist. How much changed from a few months ago to now that suddenly tanks are considered the new meta? The largest addition was the Cinderhulk, but the tank junglers getting a huge buff to their core item (and the addition of Bami's) isn't THAT big enough to suddenly make them the new meta. Laners don't directly benefit from it. At most, it made the tank junglers viable again.
From my personal experiences in game, it seems like an overreaction from the assassin meta getting broadsided by their elemental nemesis. The core element of assassins is they deal their damage in one big burst and get away before they face retaliation. Tanks specialize in dealing their damage out over a longer period of time, but are able to last considerably longer in battle, sometimes able to bounce back much faster from damage, and hold down the enemy long enough to deal that damage to them.
If assassins can't kill their mark, their only option available to them is to get the hell out. Unless they have someone to help pin down the enemy or just generally protect them from the enemy, either through buffs or crowd control, they melt in the hot sun under direct and sustained fire. Tanks by and large have exactly what destroys assassins, and since tanks received a decent boost to their earlier game, it made them a lot more capable of taking on their nemesis and winning.
The punchline is this isn't exactly new. Tanks received a huge boost in their power back during Season 4 when the Quill Coat was introduced, and what would later be remade into the smite buff from the Gromp. The short life of the Quill Coat, however, along with the entirety of the old jungle item sets made its impact quiet, minimal and short-lived.
Tanks are not the new meta. Assassins are just losing their ground from the previous season, yet people insist on bringing four AD assassins to the game regardless of how counterproductive it actually is, and this is becoming all the more apparent the longer it goes on.
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(also counts as continuing the Feral Flare's legacy)
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falling off general interest. As soon as the new jungle went up all those months ago, those 2 dominated disgustingly along with
9/10 games, it was THE worst meta in LoL's history(subjective), not to mention HOW FUCKING BAD IT WAS TO PLAY AGAINST THEM.
's rework now that they all buy
all the time, the sole interaction with them has bowled down to whether you'll get 3 crits in a row and they won't get any, or if they get crits constantly and you get only 1, or nobody gets crits etc etc.
are assasins.