a) -1 for a winning side player losing all ships and scoring no points
=> Not liked because, especially in Captain games, you could lose your only ship without making points and still prove valuable to your coalition.

b) +1 to every winning player with ships in case of "overwhelming victory"
=> according to the same reasoning as before, why not giving +1 to those who sacrificed their ship for their coalition?

c) +1 to the non-winning side player who scored most
=> This is not liked in 1 vs 1 leagues (it should not be awarded if there is only 1 non-winning player)

So given the current feedback we might:

eliminate a)

change b) so that it applies to the whole coalition, without checking if people have still ships or not

fix c) so that it does not apply to 1 vs 1 leagues.

However, the 3-1 scoring in 1 vs 1 league due to c) made me think that it might be interesting to have a different score for "close matches".. something like "marginal victory" in BM.
Maybe make a 2 point victory if your coalition scores less than 30% more than the other coalitions?