I've been comparing her to moakai, decent damage in lane and becomes more of a bodyguard outside of lane, like she can be a diver still with her E and W blocking escapes, or she can sit back and use her abilities to be a linebacker for your carries
I don't think her ult is useless, it's like bards ult, people aren't playing it right, I had a poppy ult away 2 carries in the middle of my wukong cyclone. It's a common mistake you see all your teammates dump there ults on the enemy for a wombo so it's only natural to do the same, people would do the same thing with bards ult.
I do agree with the idea that the massive displacement ult doesn't match the diver play style, but I disagree with her W passive being damage reduction, damage reduction is really powerful and I like how the bonus resistance passive encourages itemizing for tanky stats, where damage reduction is just to make guys who wouldn't be tanky, get tanky without investing gold into it, which isn't ever fair feeling when it's someone who builds a ton of damage and murders people