What is the current state of the law on appeal and judicial review?

[26] As the court in Boucher has noted parties who have failed to avail themselves of the appeal and or judicial review options in a timely fashion should be prevented from mounting collateral attacks on final decisions. Indeed, to quote the S.C.C. in Toronto v. C.U.P.E, the harm to the justice system lies not in challenging the correctness or fairness of a judicial or administrative decision in the proper forum, it derives from inappropriately circumventing them.