IMHO, wire nuts are great for connections that are not going to move
much....at least I hope my house isn't going to move much and if it does, my
electrical connections will be the least of my worries!

Connections that have stress ought to be secured by terminal blocks, rings,
spades, butt connections, soldered...etc.

In as much as the current flow thru household wiring causing enough heat to
melt solder....I'd be more worried about what is pulling that much on a 15
amp circuit to generate that much heat...leading to a fire?