Would this passive make more sense for Poppy then what she has now?

Iron Ambassador (Passive) Damage from champion attacks, abilities and large monsters grants Poppy 5% bonus armor and MR, stack up to 10 times for a total of 50% bonus armor and MR. (Decays after 5 seconds of not taking damage)

They said they wanted to focus on making Poppy a tank who can heroically charge in, I think this passive would allow her to suit that need better then what she has now.

Thoughts?