but you can reduce some of that localized stress by using heat shrink on the soldered joint.

I think perhaps the biggest argument against a soldered joint is that all too often they are just not made all that well... cold soldered, which leaves a high resistance connection... and they are harder to inspect. Whereas a crimped joint (using a ratchet crimper) is said to be "gas free" and is easier to inspect, and can be tested with a good solid pull.

In either case I would still heatshrink the finished connection. And there are some nice heatshrink products out there with glue or sealer built in that will further encapsulate the finished joint. Anchor makes a nice product for this.