Main Motorcycle: '01 Bonneville (modified)
Join Date: Jul 2018
Location: Manhattan, NYC, USA
Other Motorcycle: 2017 Moto Guzzi V7 iii
Wire-wheels, I agree with you: if you are a genuine expert at soldering, then there are plenty of instances where soldering expertly (i.e. the right amount of heat, the right amount of solder, etc.) helps rather than hurts. And part of being an expert is knowing which instances those are. I'm good at getting a nice clean soldering joint, but I'm not that kind of expert at all. Too much heat is my middle name.
In my case, I packed almost all the electricals for my custom into a tiny cubby under my Bonneville's seat, which means the M-unit is mounted above the battery, the Igniter and ground terminal are mounted above that, and a few dozen wires, connectors, fuses and diodes are layered on top of that. It was all done carefully, but the fact is, I need to move stuff around in there, e.g. move wires aside to get to the m-unit. My conclusion is that having soldered so many connections, the act of pulling the wires here and there weakened the joints, and then vibration and bumps did the rest.
If I had done only robust crimping to all my connections, the wires and terminals would have been more tolerant of the movement, I believe.