The issue is simple, you reworked Poppy into being useless.
How is she any less useless than before the rework? Hell, the rework made her not only better, but added made me fall in love with her, both kit-wise and lore. Her new kit currently has
- A MR/Armor boost plus a AoE effect that blocks dashes
- An ult that can change the tide of a teamfight(ex: Hitting the enemy ADC and/or tank away)
- A passive that gives her a shield plus range
Her old was very fun(loved forcing enemies to burn their flash from an ult tower dive), but the new one not only adds a lot more utility and tankiness, but kept a portion of her old damage along with it.
I want to slam my opponent wherever I please not TO THEIR BASE!? HOW DOES LAUNCHING THEM TO SAFETY HELP ME?!
Well, it keeps yourself and possibly if they're chasing, or send a carry far away from their team while you pick off the rest of their team.
I chose poppy so I could 5v1 as a tank. Now she is just worthless CC. Not even good cc....
So, in your book, a stun, a knockback/knockup with possibly huge range, and an ability that blocks dashes whilst speeding her up is not good CC? I think you might be playing new Poppy incorrectly, mate. And I doubt you could 1v5 a team when her old ult ran out after she's killed her target.