If you've been tanking since patch 4.0.1 dropped and noticed you were taking more physical damage, it's not just a case that you lost armor in the class changes. Armor also does less now. Poster Valen performed a test on the first boss in Forge of Souls and reported some changes observed with the way damage was mitigated. Ghostcrawler (lead systems designer) soon responded that yes, the formula for armor value and its mitigation had been changed for Cataclysm. Furthermore, those changes are in place as of now, meaning that if you feel like you're suddenly taking a lot more physical damage in ICC, well, you probably are.
No word yet if boss damage in ICC will be tuned down to reduce the streaky factor on incoming damage or not. But it's nice to know we're not all insane.
World of Warcraft: Cataclysm will destroy Azeroth as we know it; nothing will be the same! In WoW Insider's Guide to Cataclysm, you can find out everything you need to know about WoW's third expansion (available Dec. 7, 2010), from brand new races to revamped quests and zones. Visit our Cataclysm news category for the most recent posts having to do with the Cataclysm expansion.