I think it all comes down to what each individual person likes in a dog, regardless of their main quarry, big or small.
I like deerhounds, collies, geyhounds and whippets, so a lurcher that had these breeds in it would be my choice for all sorts of stuff. Whether it would be a 'top notch' allrounder wouldn't really bother me too much as long as it was pretty capable of most things.
Another thing is that I've never really had any need for a ferreting dog, as I mainly lamped, so there again an allrounder wouldn't necessarily have to be a good ferreting dog for me, but when I did do a lot of l