You forgot that MP absorb reduces DMG too. What makes Bloodmagic+MP absorb broken is that you literally heal more HP than any DMG that does not kill you in 1 hit. You are basically immortal unless the enemy can oneshot you.
+50% ice dmg and 37.5% DMG reduction is still an amazing effect. Plus if you do not use bloodmagic, it heals your MP too! With the new changes Permafrost is still an amazing set.