As boorish and obnoxious as Blueblood was, I don't see him as the type of pony who is evil and conniving. I recently read a couple of MLP fanfics on FimFiction, and he was the main villain in them, trying to usurp the throne from Celestia and Luna. I honestly don't think he's capable of that, either from an intellectual, emotional, mental, or physical standpoint.