Lol. The way you asked it makes it sound like you know the answer because you said who it was NOT. I would say the real answer to the question is The DOC. DOC said in some interview what he did for Snoop back then was more like "coaching" than straight up writing his lyrics for him. He would tell him to change certain parts or say certain words differently. RBX & Kurupt probably helped a bit too, as previously stated.
There, I spoke on it.