*TInfoil hat on*
According to the ars arcanum in RoW microkinesis, or Stoneshaping, was present on Yolen with more destructive abilities:
So there are now two Surgebinding abilities on Roshar that also was present on Yolen. The second one being Lightweaving which is something Hoid already is able to do. According to a WoB microkinesis is not capable of splitting atoms however Brandon also says that it was capable of doing that in his original dragonsteel books.
So what leads me to believe Hoid has been a stoneward?
For a while Hoid was going under the name `Topaz` in reference to him being the bearer of the first gem. Topaz is also the gem associated with stonewards. Now this doesn't really make a strong point and could just be coincidence. However in chapter 68 in OB when Shallan and Hoid is talking he mentions this:
This is also the subtitle given to the Stonewards in the quiz about the ten orders.
However he says `vow` and not instead of `oath` but that could be Brandon making sure he doesn't set off our cosmere alarms too easily.
*Second tinfoil hat on*