Having played a shielder extensively, just my two cents.
Huscarl has a magical forcefield, period.
Swingspeed is definately not affected by shield speed, feinting and raising are. How much is hard to determine, given latency and whatnot, at least for me personally.
A steel shield is utterly useless in a random fight, axes and such will shred it. Bonus against shield equals the need for high hp, low armor, shields, not the other way around.
People whining over shielding being "easymode" and whatever clearly does not know how they are played "properly"; hold off four people at once, make them hit each other, strike at the guy behind the first one in the killtrain (let your teammates flank them as you draw their attention). Hold the door-/arch-/passageway against all comers (mind the silly kicks). Cover the team from missile troops and charge the same, nullifying them (main reason to use a huscarl, after all). And so on.
A shielder fighting a two-hander, "skill" being equal, the shielder will lose. Don't bother with the "but if... / you suck!" logic. One on one, the shielder is slower, has less reach and damage. That said, there are many ways for either to outsmart the other, using the surroundings and situation to tilt the outcome.
A shielder with support (stabbing 2her, piker, missile, whatever), or in a supporting role, can kill or aid in the killing half a dozen enemies at once (well, in a row, anyway) without more to show for it than a few dents in the shield and a silly grin on his face. Yes, those truly gifted blocking, chambering, plain insane 2hers can do the same, but I have been told it's hard to block in three directions at the same time...
@Rustyspoon (just since I saw the reply as I went to post); Shielder vs shielder is far from boring, unless you think block, strike, repeat will defeat anything but the greenest fellow. ;)
Shielder rushing headlong into battle and being swarmed under or dying in a "duel" off to the side is what is giving the whole "class" a shitty name. That goes for any build/class, I know, but imho it's just easy to spot the lone huscarl being raped, compared to the various 2her/pole/archer hybrid builds.
Edit: And yes, obviously shield speed/weight SHOULD affect the attacks, hopefully there's a way to emulate that properly.