I personally do not like the look of the parti or Beiwer either. According to reports from the Biewer group that did DNA testing to find out the genetics of the Biewer, it was found there is very little Yorkie genes in them. They are the result ofgetting a mix in there. You think that didn't happen in the partis? Guess again!
YTCA doesn't want to change the standard to allow partis because they aren't yorkies and do not fit the breed standard for colour.
Call them something else and go through all the work,money, years, dedication it takes to have a new breed recognized. That would not bother anyone instead of trying to ride on the tail of an established breed so you can market them for big bucks as rare.
Here in Canada, there was a problem with some wanting Merle chihuahuas recognized. The Chi club of Canada worked very hard to not only have them not in the show rings, it has just been passed taht a merle Chi cannot be registered regardless of the registration of sire and dam.
A reputable breeder of any purebred dog and their parent club will protect that breed all they possibly can.