I don't want my sheaths to be "nice and supple". A knife sheath has three very important jobs... to retain the knife, and to protected the knife, and to protect the user from the knife.
I find that very soft sheaths sometimes won't hold onto the knife securely. And a stiff sheath will do a better job of preventing cut throughs or injuries caused by falling on the knife.
I like hotwaxing, myself, I like the look and I like the way the knife ends up fitting.
Andy