I like the idea of having NPC crafting guilds for each crafting skill. Still allow players to learn any crafting skill they want, but limit membership to just one crafting guild per character. Membership to a guild could give buffs to your specialized craft or access to exclusive recipes. Membership would not be a gate to higher levels of the craft, nothing would stop a character from maxing every craft. The goal would be to give characters the feeling of specialization without discouraging players to learn other skills.

What do people think?