Since returning from injury, Wade Barrett has debuted a new finishing maneuver. The move, which is essentially an elbow to the temple, shows that the simplest finishers can sometimes be the most effective.
Simple finishers are especially effective for heels. They can be used in most situations. Finishers that require little setup are best for heels because of how little momentum they require. If a heel can believably execute his finisher in any situation at any time, he is much more of a threat.
Big Show's WMD comes to mind. Even if Big Show is being beaten in a match, he can plausibly execute his knockout punch at any time. That, compounded with his size, makes Big Show one of WWE's most threatening Superstars.
Sheamus and the Brogue Kick also make a great example. As a heel, Sheamus could counter one move and come back and kick his opponent in the head at a moment's notice.
Sheamus makes a good case for babyfaces being able to effectively use simple finishers, too.
Even as a babyface, Sheamus effectively uses the Brogue Kick. The only modification he's made to the move is that he rallies the crowd before commencing the move. That way, the crowd can be ready and cheer loudly for Sheamus' win.
It's said that the best finishers are ones that can be used in a real fight. Barrett's new finisher, as well as Sheamus' and Big Show's finishers, can be used as reliable knockout moves in a fight.
So not only is it true that Barrett can hit his finishing maneuver from out of nowhere, but also it is true that his move can legitimately knock out his opponent.
It was smart of Barrett to implement his bare-knuckle fighting background when coming up with a new finisher to debut upon returning.