Profession bonuses are currently being calculated on one basic scale - the value of two additional gems on your gear. For the most part, this works very well - LW Fur Lining and Tailoring Embroideries replacing the basic enchants, Engineering Tinkers providing a brief surge of added stats/special effects, Alchemists getting added effects from elixirs/flasks.
There is, however, an outlier. Blacksmithing doesn't just provide the value of two gems, it actually provides two extra gems. This was a source of much contention in 4.3 when epic gems were introduced, as BS became the only profession to receive additional stats as a result (by being able to socket two additional epic gems, rather than two rare gems). Now, with the addition of PvP Power as a socketable stat, BS is the only profession able to add PvP Power as their profession bonus (at this time, there is no JC equivalent to Stormy River's Heart, nor is there an equivalent for any other profession). PvP Power will vastly outscale primary stats for damage/healing in any PvP environment, meaning that BS will become a mandatory PvP profession just as Engineering was several expansions ago. The "value of two gems" model doesn't work if one group is able to benefit in ways that nobody else can.
As I do not believe in raising an issue without providing a solution, I propose the following replacement profession bonuses for Blacksmiths:
Weapons are one of the few pieces of gear that do not currently use a profession bonus. I believe that BS should be able to apply a "refinement" to a single weapon as a secondary enchantment, similar to how tinkers on gloves stack with enchants. If implemented, they would remain in effect if the player is disarmed, and would only be enabled on weapons equipped in the main hand to prevent balancing issues with dual-wielders.
-Weighted Weapon - Attach a heavy pommel to your main-hand weapon, causing you to swing with greater force. Increases Strength by 320.
-Sharpened Weapon - Hone the edges of your main-hand weapon, allowing you more control over the point of impact with your foe. Increases Agility by 320.
-Reinforced Weapon - Coat your main-hand weapon in a dense polymer, helping you absorb the force of an attack. Increases Stamina by 480.
-Focused Weapon - Imbue a runic symbol into your main-hand weapon, attuning you to the natural ley lines of the world. Increases Intellect by 320.
-Enlightened Weapon - Remove the worldly impurities of your main-hand weapon, letting you bring forth mystical energies more readily. Increases Spirit by 480.
*edited to add Stam/Spirit options