I felt stupid as soon as I figured out that he was the smoke monster. Because they showed that the smoke monster can take the place of the dead in season 3 when he took the place of Eko's brother.

Richard only met the smoke monster once in human form as Jacob's brother. I don't think he knew that he could look like any dead person, which is why he asks him later, "Why do you look like John Locke?" I get the feeling that Richard didn't tend to question things and was left in the dark on a lot of things by Jacob as a result, which is why he didn't know about him looking for candidates.

Right and as i recall when jacob dies that basically goes against everything he told him. So richard believed that Jacob decived him for centuries and therefore richard wanted to die

@@carbrock.2854 No richard met the smoke monster that took Jacob’s brother body

It's like the man in black said when Richard asked him how he's alive "if anyone had the answer I thought it would be you" he was obviously worried that Richard of all people might catch on. But jacob leaves his people in in dark and the man in black depended much on that for his plans.