A thesis is not a list of themes. (A thesis is the statement of a claim, not a list.)
A thesis is not a statement of intention. ("In this paper I will explore the relation between Lorca and Andalusia.")
A thesis is not a list of five or six minor claims.
A thesis should not be an obvious or self-evident statement. It must be arguable in two senses. Someone, potentially, might disagree with it: "That's an arguable proposition, sir." And you can make an argument for it.
It must be novel and distinctive: not present already in the critical literature. It can't be the same thesis as that of any other scholar.