Mitch, that business about the NC Expedition having a starting "passenger" weight of 190 lbs. has me baffled. I don't weigh that much--even with my clothes on. But I don't carry any passengers along if I can help it.
Saying that a boat has nothing but size (length) to suggest that it might be fast is like saying that a car with a 500 hp engine has little else to suggest that it might be fast. Of course there are many other design factors involved in determining a boats potential velocity. If you ever get a chance to look at the hull design on an NC, you will see why they are fast.
If ultimate top speed were the only criteria for a proper kayak, I guess anyone could design a good one. My preference is for a boat that is fast, comfortable, seaworthy, stable, dry, tracks, and isn't much affected by wind and current. Oh, and is light enough to carry on my shoulder, beautiful in design and workmanship....
There I go again. I just can't help it.