Poacher's knife isn't actually that bad.
Maybe it should be ramped up a LITTLE more but i just made over 1k gold with it in a game with sejuani. If you only counter jungle when you KNOW the enemy isn't going to be there (he ganks bot lane and you are top) then you can make it very useful. you can basically use it twice while in the enemy jungle.\
I also built sight stone so could invade more and my team wouldn't get ganked cuz they always know where he is.