Poppy's Ult is Too Circumstantial, Here's an Idea
You only really use it during fights to throw away the enemy team and to peel the adc. What if we made it a generic knockup still with enemies untargetable, but we also made the huge thing created by the hammer stay as a wall so she has something to wall slam into. It adds a bit of cohesion into her kit, helps her initiate a bit rather than just her peeling power, and also has some cool wombo stuff with her e.