You are right about the current observation system, it's not great. There needs to be a better system for learning/observing/confirming information, I'm not working on it this week, but it is definitely on my mind.
Next update WILL have new cursor item placement icons to hint that there's a combination of item + tile you haven't seen before, which I hope helps a little, as I'd like to add more things like the jellyfish (would suck if you never find them).
I'm also going to be making the golden rod much cheaper, partly as an easier way to 'undo' frustrating item placements.
I appreciate all the feedback, thanks for playing o7