Why is a blanket decision to omit wāw from all nominal clauses unsound?

Wāw with Nominal Circumstantial Clauses: Omission, Inclusion and Disputed Cases

• The well-known allowance to omit wāw is entirely false
• Structure, linkage, context and resumption risk vary
• Every nominal clause only describes the grammatical subject
• Wāw is strictly obligatory in every case