I feel like part of the reason why the Unicronians are both the same yet very different from other Cybertronians is because Unicron knows jack-shit about how Cybertronians/life-in-general works, I mean why would he? God of destruction, death and all that.

So when making Galvatron, Cyclonus and Scourge it was quite literally “Yeah that looks okay, seems alright to me, that’s how it works right? Well, it does now” as he threw whatever seemed right together.