Henry I. answered 06/18/19
Experienced, Patient Math and English teacher
I don't think your proposed rule works, simply because the situation will dictate whether you need few modifiers or more of them. And, by the way, note that Twain referred only to adjectives. Prepositional phrases, for example, are also modifiers, and we could scarcely get along without them. My advice is to follow Twain's specific advice and also to aim for verbs that really crackle!
Best wishes!