What is the test for granting summary judgment on a difficult question of law?

Our Court of Appeal in the case of Franche v. Craig, 1998 ABCA 3, [1998] A.J. No. 27, when considering a difficult question of law on a summary judgment application said: Although we have some doubt concerning the plaintiff’s proposition of law, we cannot say that it is unarguable or clearly lacking all merit, or not a genuine issue. Furthermore, to grant summary judgment for the defendant on this issue would require us to decide a difficult question of law in the abstract. The evidence at trial may well be fuller, or different. Or the result of some other issue may well make this issue academic. Therefore, it may well be that denying summary judgment on this issue will not work any practical harm to anyone in the long run.