Does the opinion rule apply to evidence that is relevant and material?

In their essence, rules of admissibility are exclusionary. They exclude evidence that is both relevant and material. As a rule of admissibility, the opinion rule excludes relevant and material evidence. It does so because we leave it to the trier of fact, not witnesses, to form opinions, to draw inferences and to reach conclusions. We exclude opinions, those ready-formed inferences, because they are unhelpful to the trier of fact and might even be misleading: White Burgess, at para. 14; Graat v. The Queen, 1982 CanLII 33 (SCC), [1982] 2 S.C.R. 819, at p. 836.