Maybe it's just me, but does it seem that cloth drop rate goes down the higher up in levels you go? I was farming some fallen heroes the other day in icecrown with my pally, and after about 30 minutes or so of it, I got about 40 frostweave cloth.
Then while casually leveling and killing mobs in lower level areas on lower alts, I found that I often got 3-7 stacks of cloth (netherweave and below) after only farming some humanoid mobs needed for quests for about only 30-45 minutes of questing. I wasn't actively farming them too much, and often I got so much cloth that I ended up selling it dirt cheap in the AH (undercutting the peeps selling a stack of netherweave/runecloth/mageweave for like 50g+), or i just made bolts out of them to make bags with to give to guildies. As I head into northrend with them, I notice that they don't get as much frostweave from the humanoid/undead mobs compared to in the lower level zones.
Just questing around with my high level mage tailor in cata zones who has the "find extra cloth on mobs" thing, I get some more, but not nearly as much as my lower level alts. Granted, I'm not farming them too actively, but it seems like the cloth drop rate is much lower in northrend/cata zones. If true, I think that's why I haven't worked on my tailoring on my mage so much.



