Just a little thought and was wondering what everyone else thought.
For craft, knowledge and perhaps some profession skills what if instead of a general skill in those areas the character is specialized. The more specialized it is the more ranks you can put into it past your current level or alternatively you just get a bonus to how narrow that skill is.
For instance for Craft.
Sword Crafter: +1 bonus
You don't know how to craft anything but swords
Exotic Sword Crafter: +2 bonus
You don't know how to craft anything but exotic swords
Specific sword Crafter ( katana ): +4 bonus
You don't know how to craft anything but katanas
The bonus would be a specialization bonus so it would stack with all other skill bonuses that stack.
How does that sound?