This isn't a major, more a recolor, I suppose - but I thought it might be a fun way to revive the 'Regular' eye category.

Regular White Eye


Kitten Eye shown in
White / Blue / Crimson / Yellow


This eye type would appear as a random fail of its' own colour - i.e, you could only get Kitten Blue from Blue x Blue eyes. The pass rate would be the same as with other breed-only eyes, perhaps even harder.

This eye colour would only effect the 'Regular' eye types.