Poppy's W should ground enemies, instead of "knocking down"

This has little effect on those who'd escape with a dash, as they already have to wait out the 2.5s duration anyway. But it would allow Poppy to prevent blinks and dashes that are currently immune to her W as well-- though it's very important to note that unlike the current functionality, those abilities wouldn't be put on cooldown for a failed attempt, they'd simply not be cast in the first place.

To balance it, I'd suggest further reducing or even outright removing the movement speed granted by her W, so she can't just stick to an opponent she already knocked herself into and slowed. The fact it's only 2.5 seconds is also a balancing factor, though this could also be reduced or have the cooldown increased.

Pros for Poppy:

• The usefulness of her W would go from 45% of champions to 50%, or everyone if including flash
• She wouldn't have to be reserved as a counter-pick to Riven and Lee Sin

Cons for Poppy (aspects that balance this suggestion):

• With the knockdown removed, the ability would deal no damage (since there'd be no point where it "hits" the enemy)
• Enemies' abilities won't go on cooldown if they attempt to dash
• She won't be able to use it to stop champions getting to her

Based on the explanation given by Riot for her changes this patch, it seems like my suggestion fits perfectly into what they want for her-- they want her to get in and do her combo, without the option to just coast by and wander around the mid-range E'ing people. What this will do is prevent her W from being used as counter-engage (especially during the lane phase against dashing junglers like Lee or Xin), but give her more strength when she does as intended and initiates the fight, where she'll be able to prevent escape and any movement-reliant counter engage the enemy may attempt in that 2.5s window. (think like, she'd be able to E into the enemy team and stop their Malphite from ulting for 2.5 seconds as long as he doesn't just Q and walk out of her w)