From the official LOL Wiki
IMPALE ACTIVE: Skarner rears his stinger, rooting his target for 0.25 seconds as he brings his stinger down, dealing magic damage and Suppression icon suppressing it for 1.75 seconds. At the end of the suppression, the target takes the same damage again.
For the duration, Skarner can move freely and drag his victim around with him but cannot attack the victim. Impale consumes all Crystallizing Sting.png Crystal Venom stacks to deal bonus magic damage per stack.
Skarner instantly roots his targets when he uses his ult on them, this should render them incapable of flashing or using dashes but is currently not doing so. The suppression occurs at the same time, not after the root, and should render all skills, summoner spells and item actives unusable for the duration of Impale; which it does. The issue here is that enemies are currently able to flash away during the spell cast animation, which they should not be able to do as riot added the root specifically so they shouldn't be able to. This is a bug. There is no arguing this point. Now... whether or not Riot intends for Skarner to drag his victims back even if they managed to flash (like he used to be able to do) is questionable. They may or may not want to change this aspect of his game play and since they have not come out and addressed this matter it is completely unknown.
APPREHEND ACTIVE: After a brief delay, Darius Airborne icon pulls in all enemies in front of him.
It is a very brief delay, basically half of the total cast animation but even if an enemy manages to flash or dash out as Darius casts Apprehend they are dragged back in. This makes little sense when compared to the current state of Skarners ult as for Impale** there is no delay**. So while Darius is capable of pulling in quite possibly the entire team without room for them to escape Skarner is left with the chance to pull in one enemy who can with great skill, completely render his ultimate ability null and void.
Now, Riot often does soft buffs and nerfs to champions and claims that the changes are to "bring them in line with other champions or similar skills" but here we have a case that does not follow this suit. Darius is a bad comparison in terms of similar skill however. Volibear, Singed and Alistar all have skills that knockback or flip enemy champions *instantaneously *the way Impale is supposedly does. Their skills all effect champions that flash or dash away during the skill's activation. If Volibear or Singed flip an enemy champ that is flashing away their target flys all the way back to them and over their heads. If Alistar knocks up a champ mid flash they end their flash knocked up, if he headbutts them their flash ending position is augmented by the direction Alistar headbutted them in.
If there is a skill or champion that does not follow suit with similar skills or champions, it is Darius. His pull has an AOE effect and supposedly has a delay but acts like all these instantaneous skills that are single target. At the same time Skarner is robbed of his should be single target benefits that all other similar skills have. You can argue that it is because it is a root/suppress and that it lasts a bit longer than the others but keep in mind that it's cool down is much longer and Skarner can not attack his victim when he uses his own ult. It should be balanced and he should be able to drag flashing and dashing enemies back to him (following the logic of other champions it makes sense) but he isn't. The reason why is only obtainable from Riot and we eagerly await an answer.
