Hi Revenantus, and welcome to the boards!
I think you have some really excellent points there, and I agree that requiring the command station to be completed is a smart change. That's been added to my to-do list.
I had never really thought about suicide runs of this sort simply because on the higher difficulties (6 and up, I think), there around a 50% chance that the AI will abandon its posts and attack you when you destroy their command station. So if the planet is too overpowered, it can wind up sweeping your forces and wiping out several of your planets (or ending the game by killing you entirely, that's happened before, too). On the lower difficulties the AI doesn't do that, so the raids of the sort you are describing would be ridiculously effective. That sort of strategy had never occurred to me partly because I only regularly play on difficulty 7.
Anyway, great suggestion!