Good guys of LOTR clueless?

[Angry Hill Troll]

On a point discussed much earlier in this thread, Tolkien actually does say that Sauron was stupid, at least in a certain sense of the word:

Gandalf he [Sauron] did not understand. But certainly he had become evil, and therefore stupid, enough to imagine that his different behavior [of Gandalf compared to Sauron and Saruman] was due simply to weaker intelligence and lack of firm masterful purpose. [emphasis mine]

Morgoth's Ring: Myths Transformed, Text VII

"Stupid" in this context doesn't mean unintelligent, but rather being unable to make sound judgement: "Stupid is as stupid does," as Forrest Gump would say.

On Galadriel's statement that she knew Sauron's mind, well, his thought process isn't that complicated:

-I hate the elves.
-I hate the Numenorians.
-I want everything and everybody to do as I say.
-I want my Ring back!

Also, Sauron was just playing the part (of Dark Lord) invented by Morgoth. So really, he's just an actor interpreting a role first played by someone else (whose performance Galadriel had in fact witnessed)