This is incorrect. Leatherworking is a flat 320 to intellect with no bonus to spirit. Engineering gives ~320 intellect with the synapse springs which can be beneficial if used with other cooldowns for power healing at key times but it doesn't give spirit and may be wasted if there's not an obvious good place to use them or just contribute to overheal if you fire on cd.
The best professions are BS and either Alchemy or Tailoring.
- BS gives 640 spirit or 320 intellect and you can pick and choose which you prefer as the tiers progress.
- Alchemy gives a 480 bonus to your spirit flask and a 320 to a intellect flask which puts it on par with other crafting professions for intellect and ahead for spirit.
- The Darkglow Embroidery sims out slightly higher than the alchemy bonus of 480 spirit but if you want to make the switch to intellect then you have to go with Lightweave Embroidery which is an int proc and it's value varies depending on when it decides to go off during a fight which may give you a slight net gain but can also give you a loss compared to other professions.
- Jewelcrafting which gets mentioned a lot as a good profession only gives you a total bonus of 320 spirit or 320 intellect which makes it substantially worse than either alchemy or tailoring.
I was a JC/BS from the birth of this toon until MoP launch when I switched to alchemy for the spirit boost.