Don't get too hung up on Scotch-Loks in the wiring, AS LONG AS they are only inside the trailer. If outside/underneath, run. More important when looking at wiring, is how the electric brakes wire leads on the axles are spliced. Should be heat seal/heat shrink connectors with hot melt adhesive at a minimum. Those are pretty good but even those only last so long too. There will always be wiring splices right by the axles, because the axles only come with a short length of wire on the brake magnets and the trailer manufacturer has to connect somehow.
Other pretty important thing to look at for wiring, is how does the trailer manufacturer make the transition from the 7-way plug with the 7-conductor jacketed wire to the trailer wiring? I've seen some trailers that used a 2-gang household style steel electrical box, underneath the trailer/V-Nose! Guess what is inside of that un-sealed box? Regular old splice connectors, not heat sealed. Or even wire nuts! Yikes! Look for the 7-way jacketed wire to go inside the trailer before it goes into a junction box, to get those connections out of the elements. Also, look for the breakaway battery/battery box to be in an accessible and "dry" location, again, not buried up underneath the trailer under the v-nose. Have seen that too.
A tip on the breakaway battery. Most of the time they are forgotten, and will go dead after a year, and won't work if ever called upon (hopefully never needed). Wire in a breakaway battery trickle charger, so when the 7-way is connected to the vehicle and the +12V AUX pin is live, the breakaway battery will stay topped up. Still need to put a battery tender on the breakaway battery in the off-season a time or two if the trailer sits and is only used in winter.