Just want to mention that there are some WotLK mobs that are immune to fire damage (as mentioned regarding Explosive Shot) namely fire elementals in Ahn'kahet and Ulduar. (trash mobs before General Vezax)
Both parts of Chimera Shot are nature damage and I would rephrase the Serpent Sting part to "is based on the damage Serpent Sting does over it's full duration." except if you know it explicitly calculates the damage over 21s even without the glyph. (just a matter of wording but this might keep the fact accurate through possible changes)
As of 3.1.3 Improved Hunter's Mark is better than other filler talents like Improved Barrage or Improved Steady Shot even for your personal DPS, while the glyph isn't worthwhile with less than 3 hunter's in the raid. (Exact numbers have to be checked with the spreadsheet)
Master Marksman now solved the MM mana issues due to the 3.1.3 changes.
Rapid Recuperation is disputed as of 3.1.3 because the mana isn't necessarily needed anymore, before it was a key mana management for MM in longer bossfights.
T.N.T. 6% damage increase to the shot that does 35%-45% of the hunter's damage is more than a good filler I think.

While Lock and Load though having the potential for a big DPS boost is often doubted because of it's unreliable RNG effect.
Professions:
Jewelcrafting can give 33 agility instead of 66 AP too. (just because you mentioned the choice with blacksmithing)
Engineering gives Nitro Boosts to boots (16 crit rating and 2s runspeed increase at 3min CD), Hyperspeed Accelerators (340haste for 10s at 1min CD) or Hand-Mounted Pyro Rocket (fire damage every 45s) to gloves.
Tailoring has Swordguard Embroidery (300AP for 15s proc at 45s ICD) to cloaks.
I hope this was helpful and I didn't push things to hard.