Well, I'm not so sure a restriction in the hose would make it seem more firm. Let's say that at the point of the restriction the line is completely sealed off. Then the result would be a hard line. But introduce a small leak, and the brake pedal would move down slowly with applied pressure, as the OP described. I'm with King on this one.

Now if the brakes are spongy, then I agree they're most likely not bled properly.