Well, the role of a unit as an SC or as a Thug can change, ofcourse. If you're using a unit to solo independents in the early game, it's an SC. If you later on use it to support troops, along with several other units of similar power, it's then a Thug. I think the primary difference between "Thug" and "SC" is how much you're focussing on them, at that given point in the game, not just on their respective level of power. A Cyclops, for instance, is a respectable SC Pretender, but when you stop using your Cyclops for combat/expansion and only use it for forging, research, summoning, etc. in your home province, it can be argued that it's no longer an SC, because while it's still "super", it's no longer a "combatant".
There's plenty written about Thug builds, but give a "thug" chassis enough choice equipment and empowerment, experience, make him a Prophet, etc. and he becomes a lot closer to an SC.
And thanks for the compliments!
Maybe I'll rewrite this and stick it in the strategies index, if you all think it's useful.