If they can remove the massive number of chicken and egg recipes, and the interdependence of crafts (i.e. to do a number of leatherworking or weaving recipes, you need both leveled up) I'd be open to this.

Presently, the system is entirely to much of a mess for them to spend time forcing us into one or two craft jobs (which would also fly in the face of reason given the current Armory system. To do this they would be essentially abandoning the Armory mechanic for a majority of classes)

I'd wait until after they revamp crafting in 1.20 before we worry about specialization.

I can't see this going over well with the number of people who have spent days and weeks of their time leveling multiple craft jobs though. Nullifying that kind of time investment would just be a flat out cruel move on SE's behalf.