I apologize in advance for the long post as it is sort of three different suggestions. This thought is to give players an incentive to specialize in just one or two professions. As a not, in order for this to work, the gathering related skills (logging, mining, digging) would need to be moved to survivalist as all players need these not just they're related profession.
The idea is simple, if you have specializations in only one profession, you gain a perk that reduces your material costs by 20% (boosting to about 84% total efficiency) when any specializations in that profession reaches level 7. From here, every profession added reduces the perk by 5% (i.e learning 3 professions would drop the perk to 10%). This perk can turn into a penalty once more than 5 professions are learned, increasing material cost by 5% each. The thought is this would also reflect real world skills a little as someone who specializes in a particular job would generally be better at it than someone who does everything (Jack of all trade).
For the gathering specials, the related perk could be a 20% (or whatever the % perk it's at) chance of not reducing tool durability with a minimum of 0% chance. This would keep incentive for miners to be masons, loggers carpenters, etc.
Continuing with the last thought is the next suggestion of a new tool related skill, building. This would be related to Engineering and effect the hammer. To make this useful, I would suggest that building with tier tier blocks requires better tools. This would helps reduce the current ability to mostly skip tier 3 and go for tier 4 materials as only a builder with the +1 talent would be able to use tier 4 with a steel hammer.
Lastly, in a loosely related idea, is the hunters bow. It has always seemed odd that hunters are stuck with a longbow for the entire game. Therefore, to give better tools such as with other lines:
- Tier 1 - Longbow
- Tier 2 - Recurve bow (lumber)
- Tier 3 - Compound bow
Hopefully I have expressed this clearly enough to not be confusing. I would love to hear any other's thoughts or ideas regarding this line of thinking.