Heterochromia

We already have the UI with cats and dogs, but there's no way there's all these other things, but my sims still can't have heterochromia? I have two different color eyes myself, and making my sims is just kinda eh, I feel like if there's vitiligo, stretch marks, moles, soon to be tattoo layering, ect. There should be heterochromia especially since the UI is already in the game.