I feel like what people miss is that in the situation that was Mistborn Era 1, Kelsier was a hero. He did good because what he was up against was genuinely awful. Now, in the modern era, where there isn't a huge cliche fantasy overlord to kill, Kelsier is in a different situation. He could easily go either way at this point. He's not a villian but he's not a true good guy either, and he could easily align either way