Splitting some of the tasks from the farmer to a generic colonist role is a good idea, and adding some gathering/compass tasks to that makes sense as well. It would work especially well for new players who are getting to know the system, as it provides a way to make a few coins and earn some CXP. It would also lighten the load for cooks and herbalists if someone were willing to do the foraging.
I just don’t see combining existing roles any further than they are. As it stands, the woodsman definitely spends a great deal of time gathering and cutting; it isn’t a small role. I think combining it with some other role might be a bad idea, as would adding tasks to that role. It could have a pretty major impact on the availability of all sorts of goods (ALL of the tools except the shears require wood, as do barrels and some weapons). While the smelter’s tasks that earn CXP are limited, the hours spent mining and smelting can be pretty significant–and again, the impact on the market by adding to it or adding it to an existing role could be catastrophic, since metals are required for most tools.
Overall I think the roles are mostly pretty balanced right now, but of course, this shifts from time to time as new features are added to the game. I think it’s worth it to revisit the topic now and then from that aspect.