Britleness is definately an issue so is gas inclusion, but seeing that you will not be taking your rod to 30000ft I think we can forget inclusions. I personally would not solder over an AMP crimp. these connectors are excellent and are used in many aircraft with no problems. Just use the right tool.
ps I love solder and heat shrink. A well prepared and fastened solder joint is a very nice thing to see in a harness. Not like the large knots of connectors. If we want pretty try wax string lacing as well....

Andy