One of the pieces of news to come out of BlizzCon relating to itemization in Warlords of Draenor was there would be fewer pieces of gear with gem sockets, and that not as many items would have enchants available for them. The concern from jewelcrafters and enchanters is that their professions won't be able to make them gold anymore. Community Manager Lore chimed in with their intentions for the change, and how your actual income shouldn't change if all goes to plan.
That said, we don't think these changes have to mean that e.g. Jewelcrafting will no longer be a decent source of income. We could -- and this is purely a hypothetical example -- make the best gems rarer, which would drive prices up and increase profit margins. If you can make just as much gold (comparatively) off of one gem in Warlords as you can selling three in Mists, that'll help substantially.
I actually think it will end up being more of a rough transition for the buyers than the sellers. The buyers won't be used to paying all this extra gold for their gems and enchants, but they're going to have to get used to it because the sellers will have less to sell and crafting each one will cost more. To make up for the smaller toolbox, Blizzard could even add things such as epic gear patterns, pets, mounts, and maybe even some toys to put in our toy boxes. Gems and enchants will always be the backbone of these professions, but adding a few extra perks like that would help keep them interesting (and profitable) going forward.