Unless you have unique rewards for certain long term tasks (like unlocking new tech tree branches
there is some of that. actions have prerequisites in the form of minimum experience points required in specific skills. so as skills increase, new actions are "unlocked". technically, all actions are always unlocked, but until you have the minimum skills, your chances of success are very low. so before you can even gather nuts, you need to learn plantlore to "unlock" the gather nuts action. this models you learning what nuts are and are not edible, so you can then proceed to harvest the good stuff.
then yes I think that "appropriately rewarded" (plus the survival of your tribespeople) would already take care of things and you don't need rewards for more important things.
i tend to agree, but it still doesn't model "this is important to me". i'm not sure if such a game play feature would make sense and be cool or not. perhaps i'll have to try it to find out.
You just have to make sure the system is verbose enough so the player can tell what they can do and how to do it.
this is a potential concern - a potential issue - but not an issue so far. you find out what you can do by selecting stuff (objects, terrain, the sky, etc). when you select an action, it tells you what you need if you're missing something (skills, tools, or parts). but you won't know something is possible until you select the appropriate object. so for example, you wouldn't know you can build a raft until you find the ocean and select the shoreline, and see "build raft" on the "shoreline actions menu".
i figure the docs will have to cover what to select to trigger specific actions, although its pretty obvious - you select something to get appropriate actions. like i said, it hasn't been an issue so far - even in playtest focus groups. so it may be a non-issue. but i don't want it to be like skyrim where you have to consult an online wiki to figure out how to do stuff. the value of a game used to be measured by the weight of the printed docs. by that measure (IE docs included with the game, printed or otherwise) today's games are a total joke.