Skarner's Subclass
So I got to the 
Dev Blog late, and my original post is likely completely buried, so firstly I'm going to quote that. You can skip it to read my summary. This is a response to Riot's intention to hybridize Skarner's Juggernaut playstyle with a Vanguard/Diver playstyle. My overall point is that Skarner fits better as a Juggernaut/Warden.
> {quoted}
>
> There are already people talking about their general opinions on the spires (hint: we don't like them) and his other iconic abilities, my suggestion/question is about your intent to shift towards Diver/Vanguard.
>
> Firstly, I'm concerned that shifting Skarner towards a diver role would make him a generic fighter and dilute his class strengths. Within the Fighter class and the properties that they all share, Juggernauts and Divers are complementary in the sense that's difficult to be both at the same time. Giving a Juggernaut like Skarner easy backline access that is essential to a diver would be obviously oppressive. This is going to require the reduction of juggernaut qualities, specifically tankiness. This poses the risk of turning Skarner into a generic bruiser, and he will likely still have less reliable backline access than another Diver and even less general threat as a Juggernaut.
>
> Similar issues exist with a shift to Vanguard regarding backline access reliability, and cc reliability. There is also the risk of reverting back to the cc bot that Skarner was after the Season 4 update. It's not like that was a horrible iteration of Skarner or anything, but again, Skarner just acted like a generic cc tank, and balancing around that severely diminished some of his fighter aspects. It was too problematic to have a champion who was reliably sticky, tanky, and reliably able to kill.
>
> I would suggest a shift towards a hybrid Juggernaut/Warden playstyle. Why? Because a warden playstyle accentuates Skarner's unique abilities. His ult is far more reliable currently as an anti assassin/diver tool then it is as a anti carry tool. The only way to get the carries of decently organized teams is to flash ult an isolated carry for a pick. His e also is quite effective as a protection tool and his w allows him to to protect multiple allies simultaneously. It is satisfying watching their fed zed locked down for ages while my team focuses him to oblivion. Obviously his spires do not fit at all with this playstyle, but they only fit with a juggernaut playstyle because they make him even more of a ball of stats. This also fits thematically. While we haven't seen Skarner's new lore, I'm assuming he is still a colossal and intimidating protector of the other Brackern.
>
> Having Skarner still be an effective duelist with this shift is not nearly as problematic, because unlike a Vanguard or Diver, Skarner, would still have the weakness of weak backline access, and engage potential. It allows Skarner to be a significant threat in small groups or even solo, because trying to interfere with whatever your team is doing (splitpushing, neutral objectives, etc) becomes a risk. Skarner's stickyness can still be retained, but it would be more reliant on being a response to aggravators. This decrease also has the benefit of preventing a Skarner who out stat checks you from being as oppressive While this doesn't do much at directly solving the issue of a 'strategic niche' the resistance to engage does help with Riot's focus around neutral objective control to some degree (with being able to lock down the jungler, keep their divers at bay). Also being a Juggernaut Warden is a niche in itself, as I don't think that there really is another champion that fits in that classification.
To state this more concisely, since I was a bit distracted when I wrote that,  has historically had several strengths, that together have been problematic to balance. Ignoring the 'neutral objective control niche' Skarner has been known for his stickyness, and duelist capabilities, and his targeted cc. The problem with this is that it led to binary situations where, if Skarner caught up to you, then you were dead, but otherwise he couldn't do anything. This is common for Juggernauts, but the problem is made worse due to to Skarner's stickyness and cc. With other Juggernauts such as  you could make a concentrated effort (possibly blowing  etc.) to get away from him, but with Skarner (specifically V1 & V2 Skarner) it probably wouldn't be enough. He was also to tanky to kill. Skarner's abundance of cc, led to Riot asking Skarner mains about whether they wanted him to be a utility tank, or a duelist, and Skarner mains were fairly split in the issue. Riot tried not to push him too far in either direction and  V3 was created. Without going to much into the detail about that Skarner, he was given a lot more 'aoe' cc. It pushed Skarner in the general tank direction, leaning a bit towards a Vanguard playstyle. Skarner just wanted to be in the middle of the enemy team ccing people one by one. This playstyle forced a mostly tank build. When built like this Skarner lost most of his damage potential. There was still freedom to build like a duelist was there, but it was generally sub optimal. **The point is that Riot's previous attempts at hybridizing Skarner's role have actually dualized his role instead.** This is because the engage potential and backline access of a Vanguard would be toxic when combined with Skarner's stickyness, damage output, and tankiness, not to mention his unique ult. The unique parts of Skarner's kit already synergize with a Warden's playstyle. His ult is a godsend for his adc that is being massacred by divers and assassins. His e is targeted cc that can slow down engaging tanks, and again stun threats to his carries. Unlike a shift to a Vanguard, a shift to a Warden won't require the muting of  's unique traits.
This isn't even taking into account the thematic resonance with Skarner being a ferocious protector of his kind.
Well this is my "concise" analysis of Skarner.
TLDR; Skarner should be a Juggernaut/Warden, not a Juggernaut/Vanguard or Juggernaut/Diver
Please comment If you agree, disagree, or have questions