Hmmmm....
Shields, when I used to run w/clan members we would all get huscarls and if there were 3+ of us, it would be an easy win for our team.
Shield are VERY effective in all matches, due to how strategically important they are to preventing archer fire, and blocking points.
As for them being hard to master, I completely disagree. I've played basically every class for around 100 hours, except I mostly use polearm/2hander (the exception is xbow...I hate them so much). With a shield the game literally feels like easy mode. The upper and upper left swing is difficult for enemies to see because of your shield and shoulder movement, archers are allergic to shields, and the only thing that can hurt you is a horse (unless you are a support polearm/shielder) or if Zues could use throwing weapons. Personally I believe we should bring back the iron mace and the studded warclub back into the category of crushthrough, due to how many players are using the shield in NA_Siege.
But still, kudos to shielders for helping the team win.