*I am not a boat designer or a physicist, the following are merely my thoughts on the matter*

What some people are maybe forgetting in this wide vs narrow debate, is that with a wider boat the weight of the hulls is also futher out, helping increase righting moment. That's why it's not the same as putting 2' wings on each side of the narrow boat so the crews can trapeze at the same distance from center.

Also, when the comment was made that the easiest way to make a boat faster was to make it wider, they weren't talking about increasing sail area or anything else, because the point of making the boat wider was to help it say upright in heavy winds in the first place.

Width shouldn't effect a boats ability to pitchpole all that much, since it doesn't help you move further aft to keep the bows up. However a boat that is so wide that capsizing is unlikely can be pushed hard enough to get the bows to dig in instead.

One designer's comment that I remember well: "When you're not sure wether the craft will first capsize or pitchpole, you've got it right." Granted, he was talking about maxi cats.