It's a deep part of human nature to try and reduce things to rules, principles or items on a checklist. To reduce something down to its List is to hold out hope that yes, you too can achieve the results you desire with less thought. Just do these magical steps and voila! Instant success! Formulas hold out the allure of surety, consistency, homogeny of result. Which is, as any thinking person understands, rubbish. Doesn't matter if the topic is religion, politics, baking, writing or animation. People everywhere want the easy way. They like the List of Rules. They like the Formulas.
The greatest injustice ever done to the 12 Animation Principles as noted in "The Illusion of Life" has been a sort of calcification of the principles into these unbending rules over the years. Now this isn't universal, but the notion does exist in the mind of many. I hear it in comments often. These 12 items have been taught, memorized, ingrained. Students across the world for decades have made them a mantra for their work. The allure is there. Just get these 12 things right and your animation will be perfect. As if you somehow shoe horn these 12 ingredients into your work you'll have award winning animation.
Of course nothing could be further from the truth. You can't apply these things without thought. And there's a reason why the writers chose the word principles and not rules. Principles are a guiding thing. Rules dictate. Principles leave room for thought, exploration, advancement. Rules demand obedience. This is true for the Big-12, and it's true for any process or method noted or recorded. Don't fall back into formula thinking. Formulas are seductive. Homogeny of result isn't really what you want. If you always "do walks" like A, or if you always "do a take" like B, or if you always "do blinks" like C, well, you'll end up with stuff that looks like color by numbers animation. (Formulamation was the joking name we came up for it at work the other day.) Great animation, like all great art, isn't color by numbers. There is no formula. Just principles.
Anything I write about on this site or in a tutorial will, by necessity, be broken down into sub-sets of information for easy processing. The nature of describing thing requires this kind of analytical approach. I'm sure it's what begat the 12 Principles in the first place. However, don't fall into the trap of thinking that anything said is a Rule or a Formula for success. It's not. It's just meant to help. The real progress comes from you, your thought, your observation, your effort. So read what you like, disagree as much as you like. Use what's helpful, toss the rest. I'm certainly no master by any stretch of the imagination.
Animation principles are tools to give you guidance, not masters that demand utter unthinking obedience in their application.