I'll say this: after so many films focusing on a new apprentice or someone else taking over the Jigsaw games, it's nice to at least bring the focus back to John (and Amanda) being the one orchestrating the traps mostly on his own, which we haven't seen since at least Saw II- since by the time III came around, John was wheelchair-bound, leaving all the heavy lifting to Amanda and Hoffman. So having Jigsaw himself orchestrate things and not just him doing the tapes while someone else guides the players through the traps is nice.
Curious about who that was hanging in the bathroom, though. Since so much time passed between I and II, it could be anyone that, I assume, they just removed afterward so as not to mess with continuity.