I think you guys are overestimating Sir Michael. Remember how everybody hates Saboteur? That's because Saboteur doesn't do anything for you -- it's just an attack, and a terminal at that. I mean, the saboteur attack is at least as strong as the knight trashing attack, even with the consolation prize, because it guarantees a target and it has no upper limit. It still ends being a trap most of the time. If the saboteur gained a discard attack, sure, it would be stronger. But would it be great? I'm not sure about that.
Sir Bailey, on the other hand, is one of only two knights that is not a terminal. The other one, with just +2 actions and no card draw, is also usually a trap, as we're all well aware. But Sir Bailey is nonterminal and draws a card, so in my book, Sir Bailey stands tallest.
Think of it this way: how many cantrip attacks are there in Dominion?