Honestly it's not super reliable in Qud either, I'm pretty sure it's solely based on level so by the late game you know enough exploitable weaknesses in enemy types that it's hardly as relevant as the titles and description of the creature itself. Mostly functions as a new player telegraph of "OH DONT TOUCH THAT" :P Maybe here, the character can see into the soul of enemies and knows how much exp it will reward upon death, and players can infer off of that? Definitely think there's room for innovation here but there's probably several directions possible to take.
Aside, I read your twitter playthrough and enjoyed it, but I refuse to actually use twitter so I just lurk there on rare occasions :P It's interesting to see a dev take a full dive into their own creation but I personally think you should stick to doing that when you want to and have the itch to play. My perspective is that the work that brings you joy/fulfillment is going to be what's of the highest quality. But I'm in the visual arts so I have the luxury of saying crap like that which you might not XD