[Tyrant]

To me the difference between a Thug and an SC is that an SC can kill a whole army by itself and a thug is a raider or support element.

There are dozens of potential chassis for Thugs- you are looking for 30+ hp, good skills and decent MR. Flight, resistences, stealth, etherial and life drain are all good too. Morale is also a consideration, especialy for raiders, but you can compensate with items if you have to.
Candidates include various badass national leaders, Troll Kings, firbolgs, Ivy Kings, the devil from horde of imps, and plenty of others, but the classic thug chasis is the Bane Lord.

When you build an SC you want the best gear you can build regardless of cost- invincibility is the goal. When you make a thug cost is a big factor- you are looking for bang for the buck, especially if you need a bunch of them.

There are two types of thugs, and i'll just make up names for them now. The Mass Murderer is meant to add lethality to an army or be a raider and his job is to cut down regular troops by the dozens. The Hitman's job is to take down extra-tough enemy troops and/or SCs.

Both types need luck and benefit greatly from quickness. Mass Murderers want AE weapons- Fire or Frost Brands- and usually want regen as well. Hitmen want high damage weapons, strength buffs, attack skill boosts and probably resistance tailored to the circumstances.