Actually I was unaware that claymores had a higher rates of blocking opponents!
But to me it always seemed that attack and defence modifiers were what made all
two handed weapons if not as appealing as single handled weapons, I blame modifiers
for number of disbalancive things..
 But on the other hand is weapon balance so crucial? I don't think there's many things
that require much of effort to defeat at maxed stats and ~100 skill, so choosing any
weapon based on your character preference should get you by, few hits longer fights
don't seem to me like much of a difference. Monsters are really weak, that might be
more of a problem, so I often use poles to mush them cause it seems more fun :3 So
if your character really likes claymores I don't see why it couldn't use them as it's
primary weapon, even with all there disadvantages compared with other weapons..