For all my utility, boat and RV trailers, I purposely remove their linear "inside axle tube" wiring and replace with 10 gauge STAR design "outside the axle tube" wiring design. New 10 gauge wiring from trailer tongue's 7-pin connector, to junction box, to each wheel hub. All connections are soldered as well. Before and after design upgrade comparison is amazing. Not only better and more consistent braking power, but much higher level of safety as well. IMO, STAR design should be minimum factory build. Perhaps in time....
As a suggestion, don't waste one's time over analyze factory's default linear using 12 gauge wire against much better STAR design using 10 gauge wire. Simply upgrade to much better STAR design and enjoy.
Note: Safety support chain is optional on trailer. I installed safety support chain under my utility trailer because it gets dragged through all sort of bush and garbage land. For my boat and RV trailers, I didn't use the safety chain. But, did install wires inside the plastic wire loom - like shown in above picture.
As implied, don't waste time analyzing before and after. Simply "do the upgrade" and enjoy one's benefits afterwards. STAR design is that much better.