Your Ice Hidden Power Porygon Z would be very good with Blizzard. Could use it as a glass cannon against dragons and I feel it's DPS would be pretty good, although I haven't checked the numbers. I have a Porygon Z with Grass HP and Solarbeam so I use it as a pseudo grass attacker. Although lacking STAB, I feel mine has pretty good DPS and I use it to clear gyms with any Feraligatrs with HC, Wailords, any good water type.
Your Ice combo could be quite useful I feel, and I wish I had one with Ice hidden power.
