In a creative game like this one it would be an own-goal to not include a skirmish/sandbox mode.
Balance and challenge are great in campaign and super important in academy.
But there are moments in life when all you want to see is a metal killing machine, only limited by the game engine, ripping apart a small fleet in hud-off mode.
Hurts noone to include a skirmish mode that is independent of the campaign. You could even use it to allow public testing of new hulls and modules before implementing them in academy or campaign.
