look at what they did with TBC. Sure, things like dreamfoil are still used(Adept's Elixir), but there is an abundance of new herbs. The new stuff they made in TBC could still be used in Lich King, but I'm pretty sure they are going to make new herbs/ore etc.
I agree. As long as the tradeskills continue to have a new 75 points to develop, we will have new ore (White Gold, Diamondite, Phorium?), leather (Furry Hide, Tough Leather-scraps-tough-heavy tough?), cloth (Chillweave?), herbs (plenty to imagine), (celestial?)shards/(frostrime?)dusts/(glacial?)essences/(tundra?-okay that one's bad)crystals to gather to skillup gathering & for use in crafting professions.