Sorcerers Apprentice
Hero
This is going to mess with a lot more than just counterspells. There are a lot of features that interact with spellcasting, such as the Mage Slayer feat and spells like Globe of Invulnerability, that are now suddenly useless against these NPC "casters". I hope WotC comes to their senses and adds stuff like "level 3 evocation spell" to the description of these abilities.