Plate / Cloth Armor differences
Plate will still possess much more armor than cloth, the difference just wont be as significant as it is now.
[...] posted something similar in the Cataclysm forum, but let's look at actual numbers. A level 80 Prot warrior in Icecrown gear unbuffed has like 45,000 health and 30,000 armor. A level 80 mage in Icecrown gear unbuffed might have 20,000 health and 2000 armor. Yes, 2000 armor. We have a lot of room to narrow the gap a little. It's a big gap.
[...] Someone (Angua?) had a post awhile back that explained this using numbers. Cloth won't have as much armor as plate. But maybe it will have half as much armor as plate instead of one fifth as much armor as plate (or whatever the ratios end up being at higher levels).
Really, cloth isn't the issue, since cloth wearers have spells to buff their mitigation. Leather wearers are the ones who end up the most fragile. Mail would be bad too except that shaman can use shields when needed and hunters typically don't get hit by melee much. We just want to bring things a little closer to each other. It's easier to establish a baseline for how hard a particular attack should hit for when one dps spec isn't literally four times as survivable as another.