Just let his Q-Crystalline Slash proc it's slow on the first hit. No need to mess with numbers, no need to revert previous nerfs (despite how much I hate them and think they were unnecessary). The problem with Skarner is most junglers need a gap-closer/consistent slow to secure kills/assist in ganks. Early levels and even mid-game Skarner is unable to do this because you have to hit either a minion or champion prior to being able to slow them. Usually means you have to burn your ult and most people will just escape anyways after it ends via flash/blinks/dashes. If he could slow on the first proc he could at least save his ult for after they use their escape mechanisms and be a much more viable jungler this season.

Grab Ghost. He'll be much faster and more effective. He doesn't need a buff or a nerf. Once you have his Q, its not that tough to keep an enemy slowed unless they have a way of jumping out, like Caitlyn.

like caitlyn, graves, tristana, ez, corki, kass, zed, kha'zix, hec, nasus, j4, jax, tf, ryze, fizz, etc etc. I can keep going with the amount of played consistently champs that can easily escape from Skarner Q with little to no problems whatsoever.

Ghost doesn't help him as much as flash someone see's you pop ghost mid/late game and they will just stay away till it runs off now if you don't have reverie you will never be able to initiate as Skarner was completely made to do. It's a nice sum spell for him yes but it drastically screws him later in the game it's only really effective early game.