In general I'd say take Tailoring over BS for a number of reasons:

1) Its much cheaper to level, and will continue to be pretty easy come Wrath, just craft stuff from cloth drops
2) It goes great with DE. The normal formulas mean that it's about 20-25% more profitable to craft cloth drops into DE mats than sell the cloth raw. My team just sends all their cloth to the tailor and she crafts stuff up for mass DEing once a week or so.
3) Spellthreads - The shammy who takes it will get access to epic spellthreads to improve spell dmg or +heal.

EDIT: I run mainly with either 5 shammies or 1 palla and 5 shammies:

Shammy 1: Skinning, Eng
Shammy 2: Mining, LW
Shammy 3: Tailoring, LW
Shammy 4: Ench, LW
Shammy 5: JC, LW
Pally: Eng, BS

I know I'm missing Herbalism, which is regrettable, but I have it on a couple of other random 70s.