I did a trade today hoping to have a good fight with my own red thief and I found that if you do just 1* appear just the regular thief that I can 2-hit them (loose thief xp for that

). The only good part was when I reach the Hyenchegon (dont remember exact name, the headless stones) and I started to kill gold bots with a light npc thief

.
I think that the only basic change is that as you are allowed to carry more load there is the chance that those high levels thief appear, but dont affect the typical 1* trade.