No. Well, not really.
Answering the question, "what does my character know about this monster?"
If the sleep spell is keeping you up at night, because of confusing mechanics or soft scaling, come take a look under the hood and sample two sleep spell solutions.
While we pride ourselves on deeper analytics, there's no reason you should have to work to understand the basic game mechanics. With that in mind, we're refining the resting rule in 5th Edition D&D.
We're going to make the adventuring day agnostic as to character class. That way, everyone's going to be on a level playing field, regardless of how many encounters you run. How do we do this with linear fighters and quadratic wizards? It's simple. We kill the short rest.
The "Bag of Rats" Problem is an issue that arises with RPG mechanics that trigger upon a kill. While kill trigger abilities are intended to reward the character for disposing of a foe, they incentivize players to metagame by carrying around a lot of easily-squishable pocket-sized creatures. Explore the solutions and find out which are best.