I do like the idea of him being in a weakened state or there being a good reason he isn't so high level as a druid.
I think its fine for variance IF you get enemies who have less spell slots as well, otherwise I'd rather they follow the rules. Also replace Level when looking at a NPC with CR.
The problem with CR is that for most players say nothing. Level, however is an universal thing in games that any player will haven't a any problem.
It could mean something if you explain it to a player, what it means. Could have a tooltip when one successfully inspects an opponent it says "A Low CR means a weaker opponent, while higher CR means a stronger opponent. Be careful fighting enemies with a higher CR than your level."
