Ten minutes watching YouTube will demonstrate that amateurs are certainly capable of repairing todays devices, even down to something small like an apple watch, so small size and reparability are clearly not mutually exclusive. Why would they be anyway? Certified repair technicians aren't magic, they just have access to training, parts and tools that help.
You should see the insanely tiny pads I had to solder to on my Xbox 360 to install the RGH mod. With a 10$ solder iron, homemade flux, miracle I was able to do it. But I did repeat it and given the same incentive even if they made it smaller next time I would get some jewellers glasses and a better iron.
