In faṣl and waṣl, the issue was whether connected clauses should be separated or coordinated. In ījāz and iṭnāb, it is how much expression the intended meaning warrants. In iʿtirāḍ, it is whether an inserted aside adds an appropriate rhetorical benefit. All are governed by the demands of the situation.
Thus, not every omission is eloquent; not every expansion is defective; not every wāw is appropriate; and not every intervening clause is parenthetical. A rigorous judgment integrates source wording, syntactic relations, communicative intention, and the audience’s position.