Well, strictly speaking a Dreadnaught is just a Battleship that foregoes the smaller caliber auxiliary guns for an extra main turret. It's not even an official ship class, just a nickname since the first one to do that was... HMS Dreadnaught. Which was actually a really bad move at the time as it made all fleets, at a time when the british fleet was far superior in number of battleships to any other, start back from square one, negating their advantage in one fell swoop.
Lesson to be learned? Don't introduce advances that nullify your own forces when in fact your forces are far superior in strength and number to everyone else's. Save them for when someone else start doing it.