The pet requested is completely random. You are no more likely to get an albino than a natural pet requested. People just get stuck and complain about albinos so they seem more prevalent.
Hatched pet prices stay pretty propotinate to their hatch rarity. Nothing is really going to change that short of changing rarity.
We are working on new ways to expand pet value beyond color rarity.
And for the record, I was teaseing Rudolf in my first post. This was posted right after the release of pet quests, when there was a HUGE increase it pet sales already happening.