The halberd is this guy's weapon of choice because he's strong enough to rip apart a close-packed situation with his 'six-foot pole', and he doesn't need to be blocking very many blows with that armor.
And, you don't get what I was trying to say about breaking wrists. The idea was that Hal's sword would've been hit with such force that there was no way he could've kept holding it. You can't "take the impact" of being hit by enough force to send a truck flying.
Of course, I didn't take into account that Hal could've just lowered his blade, as you also mentioned, which is why I edited.