Tbh if Arcane and Frost were given the exact same Ice Barrier trait then I don't see why Fire can't have it too; it'd also be easier to balance too. I could understand if they wanted the traits to vary slightly, you know "spec identity", but they didn't even try and make them different; it's literally just a copy/paste.
As defensives go so far:
Fire has:
Tier 15
Ice Barrier
Ice Block
15% physical only damage reduction: Molten Armor (6%) + Molten Skin (9%)
Cauterizing Blink: 9% HoT over 6 secs.
Frost has:
Tier 15
Ice Barrier
Ice Block
+100% stronger Ice Barrier trait
12% total damage reduction trait
Arcane has:
Tier 15
Ice Barrier
Ice Block
+100% stronger Ice Barrier trait
Greater Invisibility
I just can't see how Fire's are comparable to those of Frost or Arcane. I'd much rather the extra absorb than a heal. Plus the physical only reduction doesn't help at all with non-physical damage, which both Frost and Arcane have no problem with. I just can just see it now when Fire Mages have trouble with high burst damage fights and could struggle surviving, especially given some of the footage shown with the Mythic+ dungeons and the amount of damage going out in that. Pretty sure some feedback about those high level Mythic+s ended up with certain specs being specifically chosen (Arcane being one of them) because they had so many good defensives that they could rotate.