What would you consider as "fair" line distribution?

[Bluebells and Snowdrops]

Personally, I think skill and positions are the most important factors. I would rather listen to a song that sounds good, but the members don’t have equal lines, than a song where all the members have the same amount of lines, but some do them clearly can’t handle it. Members shouldn’t be given more than they can handle while sounding good, not even in the name of “fairness”

I’d say a “fair” distribution is where the lines are distributed to the members that best fits/can handle them. Main/lead vocals/rappers should get more than normal/sub vocals/rappers, since those positions indicate that they are better at that skill. Dancers who can’t handle too many lines, should get compensated with center time in the dance, IMO.