Dear family search,
I have two ideas about the appearance of the family tree.
1. My paternal and maternal ancestors could be marked with different colors.
2. The farther the ancestors are, the fainter the color could be.
Marked where? On trees, or on profile pages?
The Fan Chart with the "Family Lines" option selected is nearly exactly this: it's four colors instead of just two, but they fade out as you get further from the center person.