What is the legal test for dismissing an action under the Rules of Civil Procedure?

There is a high threshold to dismiss an action or the striking of pleading under the Rules. See Langenecker v. Sauvé, 2011 ONCA 803 at para 5: It should not in any event be exercised without giving the plaintiff an opportunity to remedy his default, unless the court is satisfied either that the default has been intentional and contumelious, or that the inexcusable delay for which the plaintiff or his lawyers have been responsible has been such as to give rise to a substantial risk that a fair trial of the issues in the litigation will not be possible at the earliest date at which, as a result of the delay, the action would come to trial if it were allowed to continue.

The Court of Appeal has consistently stated that striking pleadings is a remedy of last resort only to be made in exceptional circumstances where no other remedy would suffice to deal with the non-compliance. See Mullin v. Sherlock, 2018 ONCA at para 33.