So, you want your players to have your style of fun, and if they have a unique idea that isn't allowed by the rules doesn't break the game, and isn't even equivalent in power to optimized builds... you want to shut them down?
You're missing out. Whether we're talking about the awakened wolf monk, the order of Krull/Glaive fighter monks, or the thousands of homebrew spells that players (and I) have created over the editions, the changes we've made to the rules are what makes my world distinct and uniquely fun.