Bigger ships are expensive because they are big, not because they are a "Level 90 Legendary Sword of Doom +100500 Fire Damage". Lots of bonuses come with the size and the cost (bigger guns, thicker hull, more cargo, ...), that's what you get for the money, not the ability to "press X to win".
+1
I would personally prefer to have the insurance be non-lineair. The 5% seems ok for most larger ships, but doesnt really work for smaller ships. I'd say it should be graded: say 25% for sidey to Viper to 2,5% for condie. Currently my Viper is like 150k insurance, which is peanuts.That said, bigger ships could definitely use a profit buff or a repair cost reduction, to make maintenance more manageable.