Not a good comparison IMO. A city is not a solitary entity like a planet. Every city built has powerful defense from the start if it is within the borders of a nation with a military. A planet invested in a by an empire existing in a universe where many empires vie for resources would most certainly equip such an investment with at least some defensive capability.
I guess my problem is I want things to not only be balanced, but to also make sense. To me the #targets should be largely a factor of size, further influenced by ship purpose (battle, transport, etc.). A large ship (the colony ship appears to be a small planet with a gargantuan ship built around it) would likely have way more than 1 point of fire. It may not have powerful guns, but I guarantee an enormous ship would have more than one. Likewise, a planet would have to have multiple points to attack from on all sides.Similarly Colony ships / Outpost ships are more civilian ships imo. If you want them to have greater defense at all times you can fleet them up with some destroyers or some other offensive ship.
I feel like planets and very large civilian and other non-warships need higher targets but should have low initiative and low to moderate attack. I also think the cruiser, dreadnought and energy array (currently an array of 1 gun), need more targets, but whatever, I guess I'm the only one who finds the current numbers very odd