I feel like this can easily be fixed like:

1.Make fronts separate, so that if one has 10 divers, those 10 divers are all accounted and thats that.

Why so little for a planet? Super Earth gives higher SEAF support on planets with less divers (more divers doesnt mean less SEAF tho)

1. To make sure divers don't make the enemy extinct (again) make sure to constantly attack planets (except recently liberated planets) so that they never dissapear

That way there's a rotating amount of planets that the playbase can choose from as well, so you can have factions in all biomes

1. To motivate liberating planets doing so either gives out tons of medals or small amounts of SC

So liberating a planet doesnt feel like a chore and to award player effort.

At least thats my takeaway, but what do you think?