i actually like very much armor of december on raspy.
every melee opponent can be simply
1)Sub zeroed through cheat or stone
2) push away thanks to the upgrade gainin +1 armor in the process( no need to rely on Snow Storm)
3) do horrible things to the opponent
Simply put it rasputina becomes melee immune and is able to cast directly bumping her efficiency a great deal.
shattered heart is imho overvalued, as mirror points tend to dwindle rapidly during the game.
you usually get some goodness out of it but for the first turns.
armor gives you a bump in resilience and an awesome built in mechanism for escaping melee, you still have the mirror option, but you can live without it