This is a minimum risk strategy really. If my speculation is wrong or the prices drop instead of rising I won't really lose out. I already know I will use all these materials in crafting and as a new tier will be available the demand for enchants, gems etc will be high.
I have several bank tabs full of Ghost Iron Ore ready for smelting/prospecting as needed as well as a large amount of Trillium bars and Magnificent Hides ready for crafting cooldowns so that I don't get stuck with a day or two where I can't use CDs to learn new recipes and gain the new crafting materials. With the new Engineering mount requiring 30 each of Living Steel and the new engineering craftable (Jard's Peculiar Energy Source) both being on a daily cooldown, it could be a long time until these reach the auction house. I've also stocked up on Golden Lotus to make sure that I can keep myself stocked with raid flasks for personal use (or sale if the price goes up on my server to make them a viable selling option) as well as to be able to transmute gems if my stocks start to run low.
Show Me The Money!
That's dropped from last week by about 63k but I'm not worried as I expect to make that back with interest once the patch arrives!