Iceman because overall he has more uses and less weak matchups than AA. Theres very few situations where iceman would be a bad champion to bring in. He has really good damage output, immunities, damage cap, high armor and evade counte. AA has insane damage but if the opponent is poison immune he is very gimped and if the opponent is bleed immune his damage becomes less than mediocre. His ability accuracy reduction is great and is one of the best options for electro, magik,evade champs and thorns nodes but since iceman handles evade champs and if a bleed or poison immune champ is on thorns AA is severely gimped putting iceman over the top. On top of that iceman doesn't need to be duped to be a god tier champ while AA does so just another point for iceman
Iceman has more versatility. But AA is a machine for damage output if the champ your fighting has no poison/bleed immunity. Which is why he falls second place to iceman.
Comments
Iceman
1. Ice Armour
2. Cold Snap
3. Immunity
Great champ with many uses in the game. Great offensive or defensive.
AA to deal with everyone else.
We have AW full of Nightcrawlers on the north path, Magiks / MDs on others. depends which path you regularly run.
Iceman is good for everyone, except magik...aa is good against magik but suck against bleed or poison immune, or immunity node