Another vote for solder and shrink tube for a permanent and very durable repair. This joint is also very water-resistant.
However, for splices that are not exposed to the elements, this is certainly overkill. I prefer wire nuts over crimp connectors because they provide a strong and obvious mechanical connection, with lots of contact area. I have seen so many crimp connections fail, I have lost count. Mostly due to bad technique.
With wire nuts, the open end should be wrapped with tape for added strength, and to prevent the remote possibility of something getting in there and shorting it.
One disadvantage is that wire nuts take up a lot of space, and do not lay flat. Can look messy, if aesthetics bother you.
Fire risk is zero on a proper fuse-protected circuit, unless the brief spark ignites something.
Best of luck.
1986 300E 5-Speed 240k mi.