Actually I know quite a few opi docs, though that doesn't really matter. The reason I didn't use them as example is that they'd be in the middleground on the delta changes. The effects of delta changes between opi and trox or nanomage wouldn't be as extreme as trox to nanomage, as intented.
Of course there are preferred breeds. I didn't say there aren't now, did I? However many professions had more then one prefered breed at some point. Doctor, the profession I focusing on is one such profession where both soli and nanomage are the prefered breed.
There is the option of doing the trox and opi doc though, and you get a bunch of disadvantages but you're not being the cookie cutter build and you can do some other weird stuff that the cookie cutter builds cannot do.. this is even more true with the upcoming breed perk changes.
Contrary to what you think, even with most using the preferred breeds there is diversity by the simple fact that not all pick that one and take some more or less small disadvantages. With new breed perks there are even more options for different builts.
Those perks will add breed differences and will hopefully produce more diversity. Give it a chance before wanting a cookie-cutter best of all possible breeds for the different professions again.