Personally I think these abilities should have a grounded effect:
E: Not only is her win rate pretty bad compared to the other enchanters but E when used on an enemy is useless. Why would Lulu sacrifice a big a shield for allies in exchange for doing a little extra damage to enemies. By giving her E on enemies a grounded effect, there becomes a much bigger decision for the player. Should I stop the player from dashing away/ getting into the backline or give main carry a big shield to ensure they survive a diver/assassin?
E: Compared to the other engage tank supports, he doesn't offer anything better. He has to use two abilities just to engage and can do nothing but walk around with his E and ult while the other engage supports use one ability to cc a target, then can use the next, only for someone mobile enough to just dash away as soon as that cc ends. By making his E make nearby targets grounded while he is getting stacks, they can't dash away and increases his chance of a successful engage. His E would still have counterplay because you can still use CC to prevent him from staying near a target.
E: Compared to the other juggernauts, Skarner struggles very hard to stay on his target. His slow isn't very useful when the target can still just dash away and treat the slow like it's nothing. Yes he can use his ult, but as soon as his ult ends, the enemy can still just dash away. By making his E able to ground opponents, he can perform his job much better while also having a unique role compared to the other juggernauts. A juggernaut specifically designed to counter assassins.