toucanbuzz
No rule is inviolate
What? No. Kits didn't change any class mechanics, and they didn't become their own class. Some were OP, like the bladesinger and cavalier, and some were essentially just fluff. Most just gave a minor benefit, like the Myrmidion (get an extra weapon specialization and that's it).
Without getting too far off the thread, we're probably talking semantics. Most would consider Arcane Archer your class even though, technically, it's your subclass. Kits were in essence the first attempt at subclasses. To show those who might not have seen AD&D , below is a snippet of the "Convict" gladiator from AD&D Dark Sun, a subclass of Warrior using the Warrior XP table that had thief features and preset proficiencies.
But when TSR pushed for "more more more," we began to see some goofy stuff and not just limited to classes. Some of the adventures got goofy too. Which again circles back to my thanks that Wizards is taking it at a moderate pace, quality over quantity, despite my desire to see certain material (like my beloved Dark Sun).