@Roccandil I think RNG should still have a part. Artificial extensions to games make them longer, and grinding becomes less mechanical. I reckon you have an amazing idea, however, I personally believe that removing RNG isn't an option. When I got to this test, i was happily surprised that trees didn't give 5 twigs every time, regardless of tree. Variation makes the game more fun.
However, I believe, coming from your idea, the knowledge system should give a higher chance to drop rarer loot, such as rabbit feet. For example, at 0% knowledge on a rabbit you have 5% chance to get a rabbit foot, at 25% knowledge, you have a 10% chance, at 50% you have a 15% chance and at 100% you have a 20% chance. Considering how fast your knowledge goes up, and that rabbit feet are SUPPOSED to be rare, even 20% is a bit high potentially, but it's a rough draft ^c^
As much as i know some people hate RNG... for the most part, it keeps the game interesting. Seeing the exact thing over and over gets stale very quickly. RNG is the staple of most games today and it adds major replayability.