You're forgetting what old skarner had to deal with.
Like I said, skarner wasn't the issue, it was skarner's metagame that was always the issue.
Lets look at the top usage korean picks for this patch:
Top lane:

Poppy is tanky af and skarner and his laner usually won't have the damage to kill her early, mid, or late game as she just runs away with increased movement speed. Jayce will just slap skarner away from him. Maokai isn't too bad for skarner to gank, actually see this as a top pick in korea surprised me. Fiora can parry his E pre-6, or save parry for his ult if she has the reflexes. Riven is another case of too much mobility for skarner to handle.
Mid Lane:

Viktor's W makes it tricky for skarner to actually catch him in a gank. TF brings ghost so he can actually outrun skarner, additionally gold card. Ahri is ahri, even if skarner makes the biggest outplay of his life, he can't outplay her just ulting away after he waste ult, and thats if he even catches her in the first place. Ori's shield makings dueling her risky, this ain't too bad for him otherwise but her bring ghost primary screws him. Syndra can just push him away, and because skarner is all in, she can just 100-0 him.
Jungle: I'm not gunna bother with this cause a) korea's jungle is way different from NA, b) I don't think I need to explain the difference between skarner and elise.
Marksmen:

Skarner can't catch ezreal, jhin isn't too difficult for skarner, but he does have a slow and a snare. Cait has the kiting range and traps to really screw over skarner, its less about catching cait and more about if you can actually 1v1 her with skarner. Vayne same deal as cait but you might not even catch her. Jinx is exploitable, just her E is a roadblock.
Support:

Stuns, knockups, lanterns, skarner can't catch their ADCs easily.
As you can see, there's nothing pre or post rework skarner can catch. You can say "well pre-rework skarner had perma stun" my point is to say in this meta, there is no walking up to people for the perma stun, and for post rework, there is no walking up to people for the ult E stun. This meta is about being able to get onto people easily, and then stick to them and 100-0 them before they can react or move.
This is why
are so good compared to
, they can go over a wall and AoE stun a team to lock them down, they're hard to telegraph or predict their engage. Skarner has to literally give the enemy a high five inorder to engage a fight and everybody see him coming. He's not consistent or as effective in what he does.
Skarner isn't BAD though, he can easily flash ult somebody, and there's the game in his hands. Sej and Zac are mostly peel for their team but if their team isn't doing well, they'll lose the fight. However skarner has the stuns, shields, and damage to hyper carry with his engages, often doing most of the damage when ahead. Its just a matter of him being useful consistently, you won't see a 0/5 skarner do a good engage running in with few items, but a 0/5 sej or zac will sure as hell make an impact in teamfights still since they can get on people without much to stop them.
A level 3, which would you rather have. A
running into bot tower to stun people as they CC him, or
who can just E directly on them with little reaction time and get out alive? Its just not a good meta for skarner with him being weaker than other champs that do his job better, he's just good for what he does but not better than other stuff.