This is not my thinking. I saw on the blog "Why Evolution is True" a discussion in the comments about Brahms's rules for composition, which I'm assuming were established at the time and which are listed here, that many composers during the so-called Classical period followed. Bach was another adherent to the "German" guidelines. (The commenters claimed Vivaldi didn't follow the rules because he wasn't knowledgeable to be able to do so. I don't know about that but- setting the Alan Alda movie aside- I love the "Four Seasons".) Because the "rules" such as four movements in a symphony are often followed so closely, when they are departed from, as with the storm in Beethoven's Symphony No. 6, the results are surprising and delightful.

I realize these are in very different moods but to illustrate and compare here is a sample of Bach:


And Vivaldi: