So, as many people know, when you nurture a sylesti, you have a slim chance of getting an essence of that species. I nurture a Bulbori, I could get a Bulbori essence. And while there are a lot of good ways to get what essence you want specifically, what if you could filter the nurturing grounds so only a specific species will pop up? Want a Luffox essence? Select Luffox and nurture away. I imagine it would be a simple drop down box next to the other options in the nurturing grounds.

I also think this would be a small way to get nurtures up. If people think they have a chance of getting their specific desired essence, they may nurture more. (I know I would!)
This could be a slight issue with fabled species getting a mas amount of nurtures, but I don't imagine it would be too big a difference because a lot people do projects and other essence requiring things with non fabled species. And the chance of getting an essence is still so small I don't think there would be a problem with too many essences getting awarded.

Krinadon has specifically stated that this will not be a feature. Reasons that a) it would likely severely skew the amount of nurtures species got, with people more likely to nurture more popular species and less likely to nurture unpopular ones, and b) it would probably make a bit of a mess of the nurture boards during fest (especially with the new nurture system making it all smoother to nurture for a long time on the nurture page, and the new ability to select specific people's hatcheries to nurture with it)

Thanks for letting me know! I was unaware of this :)