Probably is because all the other juggernauts were really tanky just like poppy, and they all came from older champs. Think about it. MORD, GAREN, DARIUS, AND SKARNER. The were all tanks right? Well, so is Poppy! Oh yea, btw, Yorick and Taric are getting reworks after Poppy.
She's a tank.
She has too much mobility, so she's more of a bruiser.
She's a tank, looks like
Tank: High Defenses, Low sustain damage (but moderate burst), Good initiation tools, and Lock down.
Juggernaut. High Defenses, Moderate Sustain damage, decent sustain (and in turn good dueling power), but slow, with little to no CC.
I'm not sure if the new poppy would cleanly fit into either of these catagories. (not until I see the stats) Her e is her only real engage potential, but has a counter to being dived, And her ult is her main source of hard CC. Perhaps she would be a Bruiser/Duelist/diver.
I think she is a light fighter like trynd of yas. You can build them with no defense and all ad as they have an op defense gimmick like yas wall or jax dodge
She's more a long the lines of a tank. She has peel to keep away assassins, and even a big aura of "fuck you" to anyone trying to dive the back line, as well as innate tankiness from her W
Also, if you notice the juggernauts don't have a gap closer. Poppy does
She also doubles as good initiation, air go charging into the enemy team with E and popping W to keep them from escaping
