Intelligence of Orcs

[Alatariel]

I doubt neither Morgoth or Sauron spent much resources on the education of Orcs

Just because someone is uneducated does not mean he is unintelligent.

it is true that we never meet an orc Gandalf or Galadriel

Yes, but Gandalf and Galadriel have both been on ME for thousands of years. Given the same lifespan, an orc could probably reach the same level of wisdom. Then again, this is picking out two of the most wise people in all of ME and then measuring an entire culture against them. This would be like taking Socrates and Aristotle and comparing them to uneducated people in a third world country. It is not a fair judgement.