What is the substantive question of onus on the applicant in a summary judgment action?

As to the substantive question of the onus resting on the applicant, I would refer to WP v. Alberta, 2014 ABCA 404, 2014 CarswellAlta 2152 at para 26: Summary judgment is therefore no longer to be denied solely on the basis that the evidence discloses a triable issue. The question is whether there is in fact any issue of "merit" that genuinely requires a trial, or conversely whether the claim or defence is so compelling that the likelihood it will succeed is very high such that it should be determined summarily. Does the record establish sufficient facts upon which a fair and just determination can be made?