Poppy rework is probably the one where we can have the most influence in. What do we want to keep? Her passive? Her Q? Her Ult? In my opinion, Poppy is supposed to be a TANKY yordle. Like Leona, but small. She should get the
treatment. Just like with poppy, there used to be two ways to play him: Full AD or full AP. After the rework, Sion is a tank. Played and built as a tank. I think Poppy should have the same feel. Currently, she has her passive, W and ult that make her "more durable". She's very tanky... But... She doesn't scale with tankiness. There is NO reason to build tanky items on her. Tanky items just reduce the effect of her ult. I think her ult should be completely reworked. No more complete invulnerability anymore, please! It's fine on a champion like Tryndamere, because he's supposed to be a full offensive warrior.
I think a better ult for poppy would be instead of making herself invulnerable to everyone except one, make everyone else invulnerable to one person. You challenge an enemy to fight you. He will not deal damage to anyone or anything else. The cooldown should obviously be reduced, because it is a complete shut down during teamfights. This ult would be really versatile as it can prevent the enemy from taking your turret, or prevent the enemy jungler to smite baron so yours can easily steal it. This would probably push her a bit towards the support role, though, but she'd still be fine top if she also gets damage bonus. In the jungle, she can come in after your laner engaged to safe them at 100hp and finish the enemy. Maybe for interaction's sake there should be a limit to the distance of its effect. Or you need to be in combat with the opponent for the ult to last longer. I'm in favor of the "in combat" rule. It would be silly if you challenge the opponent and then flee so he can really do nothing. If you have to stay in combat it cannot be abused this way.