first - if you are basing your thread off "tags" then just delete it , tags is something to help lvl 1-10 players to understand what the champ is supposed to be doing.
second- her passive is NOT as good as you think, some guy did a math on it in another poppy QQ thread and its really not 50% reduction like you think ,100 damage does not get reduced to 50 it gets reduced to 88 or 77 or something like that.(that may be bull**** of course but i saw no one correct him and the thread got plenty of reads and responses)
and to some others who think poppy can carry games, she really cant unless you feed her ALOT of kills and what champ cant carry games when fed alot?
also l2build megatron cloak , it just gimps her damage. later upgrade it to Banshe veil
For Example: if Poppy has 100 armor (50% reduction), and her passive procs (another 50%) and takes 100 damage, it'll reduce the damage taken by 75% and not by 100%
(100 - 50%) - 50% = 25
Not the best way to explain it, but I don't see how 50% reduction could be any less then 50%. He might've been talking about how it isn't a guaranteed proc, but I don't think it would be possible to work out the exact number of hits Poppy takes in a fight that don't proc it for every possible situation.
You're right that tags are mostly meant for the lower level players, but they still lay out the intended role for those champions. Alistar can play the caster role very well (too well before this patch) but he was meant to be a tank, and that was his most common use before dreamhack.