Having consistency I think is what a breeder strives for within their lines, and I beleive each breeder has that within their program...
I also believe that having diversity within a breed is beneficial, in sorts not to breed yourself into a corner. One of the reason I chose to have dogs from 3 different kennels for my breeding program...with only one line running thru your dogs I would say one is not really starting anything as to a breeding program...simply continuing on with someone elses breeding program...to truely say "we have our own line of fill in the blank" there should be some kind of "forging" something new.
I breed for dogs between 35lbs and 40lbs, medium coat (as i do live in -30c 6 months out of the year), solids are more then welcome and I would say embraced, solids are ALWAYS involved in our breedings which does lead to more solids in my lines (which i think is a huge factor in people here not "recognizing" the coolie :as merles have been the choice coolie to "show off" on this forum), I want coolies that can jump, run for days, I like a finer head with pricked ears but love my semi pricked just as much...i like my dogs to mature around 18inches to 20inches, and most of all be smart, sharp and have a excellent emotional control and off switch...cuddle bugs are my thing...we wanted to create a dog that can work all day in your sport of choice but that will want to snuggle up and watch a movie with you if that strikes your fancy...
As pointed out before, breeding for LOOKS and looks alone (for whatever reason: consistency in the breed, producing more merles because they have better resale, wanting pricked eared dogs only etc...) will only do one thing: be detrimental to any breed, not just the coolie....it only leads to unethical practices IMO (merle to merle, culling pups, father/daughter breedings, etc...)
I can only speak for coolies as I have not been involved in breeding or working any other breed on stock. As a dog trainer for a career I can say that anyone getting a Avalon coolie knows exactly what they are getting, very consistent...just today someone from Aus joined the German Coolie group on facebook and posted a pic of their little boy and I knew exactly which kennel he came from, right away...ear set, shape, fine head, straight back, white feet....even in his slight tilt of the head for the picture...just screamed at me...trained coolie eye that all. Because the dogs posted about are absolutly beautiful but my eye is not trained in them so i am not seeing what some of you are seeing...