Looks very slick and clearly a fair amount of work and thought behind it. Initially I questioned why you wanted to go wired when the whole point of IoT seemed to be wireless (particularly since wired networks for small kit has been around for a long time in many guises). But perhaps most users might be too young to remember those, and having Arduino plug'n'play sketches is hard to beat.
However, one thing that does stand out is the way these are wired - daisy-chained. Fine if kit is close together but if you have one node here and another that way and another that way it's a lot of wire running both ways up a conduit. Also, if kit gets removed you need to plug in a connector to join the wire ends (or isolate that run if you can). The ability to connect into the cable anywhere (i.e. having a bus topology) would make life simpler for the user, I think. Maybe it can already do that, but if so then perhaps the diagram showing how they connect should reflect it.