I don't think this is opinionated. Some physical or contextual similarities have to exist between the classes and Pokémon. There have been plenty of speculation posts before, like the recent one about guardian angels, and they have not been shut down.
And @Kardora, Chesnaught is more like a paladin than a knight.
"In game terms, a Paladin is thus typically a Warrior character first and foremost, proficient with heavy arms and armor. Yet at the same time a Paladin is gifted with blessings or magical capabilities such as healing, protection, and countering evil magic (including undead), albeit to a lesser degree than a true priest or cleric. "
Paladins are tankier than knights and are more defensive than offensive, hence Chesnaught's bulky dome-like shell, high defences but low speed, and its access to Spiky Shield.
@sumwun mages use magic.