Sword&board is all about battle awareness, some feints and good momentum, blocking is super easy.
2H/polearms requires great battle awareness, good dodging skills, good attacking skills and excellent blocking skills. Many people try to play 2H but only portion of them have good scores and those people can play any other class and be epic with no problem at all.
Not true. Manual blocking isn't any harder to me than blocking with a shield. Maybe a bit easier, more room for mistakes in distance control. And distance control plays a huge part in 1h, it's a no-brainer with 2h. Attacking is also harder, much harder... and easier at the same time. With 2h you can just swing your mouse around and make any attack you want to, doesn't really matter, but with 1h it's easier to miss and if you do the wrong attack you'll get spammed by decent players. On the other hand, against most players you can go for hit-block-hit-block routine until they fail. Easier to kill those kind of players with 2h earlier though, due to more trickery being available to you with feints and footwork.
Sure, it's easier to be bad-to-mediocre sword&board because you can hide behind your shield and only attack when you have a sure kill.. but it's not much harder to go spam people with long a weapon, getting a kill or two before you're killed.