If someone leaves in a ranked game
They should take the LP loss for all five members and the remaining four get loss forgiven. To penalize the other four individuals for remaining in a ranked game in an entirely unwinnable situatin is bullshit. You cannot tell me that this could be "exploited" because leaving is already a punishment in itself. All this does is puts the 100% onus on the individual leaving. To those that are somehow arguing that you want to be able to remain toxic in ranked games and this system could be exploited, implementing this punishment to leavers of premades would immediately solve your non-existant issue of "omg premades will abuse this"