So I'm reading WoR again and came across the beginning passage to chapter 41 that at the end says one of the ten did not abandon there arms. Not much context as to what this passage meant but made a thought pop in my head. It made me think at first that perhaps it meant the Stonewardens since Taln was presumed their founding Herald and he was the only Herald still fulfilling his duty, though not necessarriily by choice. This led me to think maybe they had never abandoned their duty as believed. But that was negated by the fact that the Stonewardens were one order seen abandoning their duty by Dalinar. This still left and idea in my head, however.
What if one of the orders didn't abandon their duty? What if instead they went into hiding, leaving everyone to think they had like every other order, but in secret were still on Roshar, biding their time until a new order of Knight Radiants came?
It was just a thought. One that doesn't have any real evidence to back it up, but still would prove to be an interesting plot element if it were true. Feel free to point out problems with the theory, or your own ideas for which order it would be if it was true!