Player: "Hey guild, which crafting profession should I take?"
Guild: "Depends, what are you planning to do in this game?"
Player: "Uhh...I am not sure. I like to pvp but I also like to raid as well."
Guild: "If you like to pvp and raid, I'd go with either engineering or alchemy. Both professions provide great benefits for both environments. As an Engineer you can make bombs, grenades, and etc to help boost your dps or pvp and with alchemy you can make buff or healing potions which also benefits pvp and pve."
Player: "You're right, I think I'll go with alchemy."
However, a player receives tremendous benefits from alchemy or engineer/cybertech. First, they're consumables and second they're consumables that provide a huge boost to their characters. But another problem does arise from this. Since everyone knows that the consumable skills have a much greater value, everyone picks them. So if everyone is an alchemist, then the skill itself (at least on the open market) is worthless. If everyone can craft their own potions then where is the demand for potions?
So really it's a sand trap. In theory alchemy and engineering provides the best value in terms of crafting in MMOs. However, in practice since the two tradeskills have the most value the majority of the playerbase learn those skills, causing their value in the market to plummet because the supply side far exceeds the demand side, making the two professions worth-less.