Lol interesting topic. How does one defeat someone using two shields though? I guess feinting is key here. Or getting someone to help you kill him. Or maybe 2 more people if he is really skilled in using 2 shields. Or keep attacking until he becomes exhausted and keep him on the defensive since depending on the shields he's using, the weight could exhaust him quickly.
Nnnnot really. In real life, two shields would be generally worse on the defense than a weapon with a shield, since you'd lack the ability to constrain, counterattack, and threaten at a greater range that a weapon provides. Much of the defensive efficacy from the combination of weapon and shield comes from the ability to defend at multiple different ranges simultaneously, or to defend at one range and attack at another (thus why the buckler, IRL, was the most advanced shield and the last to develop - it's the most active). The second shield doesn't offer you much additional protection, mostly covering angles that are already seen to by the first shield.
But hey, it looks cool, and in video games, that's way more important.