I doubt the gems will sell even for you guys, because the green MoP gems will almost certainly be better and they'll be cheap due to people leveling their jewelcrafting and wanting to just offload the stuff they're cutting to level. I could absolutely be wrong, since every server is different and the RP servers are even quirkier than the others, but I have my doubts as to the viability of those. The enchants is hard to guess at until we know what enchants we're getting in the new expansion. For example, there were no agility enchants to gloves and cloak from Cata, so for hunters/rogues/ferals/enh shamans, they've actually been wanting those Wrath enchants the whole expansion. Mongoose was considered a decent enchant throughout Wrath too, so there's certainly some potential there depending on what they do.

Hmm, glad you mentioned glyphs. While I constantly sell those and make them based on demand, the price for herbs has been skyrocketing already and we're months away. I should probably build up a very nice supply of ink, because even if they really do away with prime glyphs, there will still be a need for the others for all the pandaren whatevers. I won't go too crazy until we see more what's happening with inscription, but they did promise not to kill it, so...