so, first of all, Kelsier was actually a very brutal person towards people who abuse their power, we saw that over and over again in mistborn, and I doubt that has changed much. SA has largely been about people who have power, many of whom have severely abused said power, and I imagine people like Jasnah Kholin are no exception.
Kelsier also had large and grand plans, but he was also good at working with teams to accomplish bite sized goals. I imagine one of the things Kel needs is resources, investiture particularly, which seems to be the goal of the GB on Roshar, likely not as a tool to for enrichment, but as a means of acquiring a resource for use in some grander plan. One piece of a much larger thing.
Kelsier also, like the Fused, would likely have an identity that slowly consumes him - in his case, his identity as the Survivor.