Actually Canada does have such a clause. Section 129 of the Constitution Act, 1867:
Continuance of existing Laws, Courts, Officers, etc.
129. Except as otherwise provided by this Act, all Laws in force in Canada, Nova Scotia, or New Brunswick at the Union, and all Courts of Civil and Criminal Jurisdiction, and all legal Commissions, Powers, and Authorities, and all Officers, Judicial, Administrative, and Ministerial, existing therein at the Union, shall continue in Ontario, Quebec, Nova Scotia, and New Brunswick respectively, as if the Union had not been made; subject nevertheless (except with respect to such as are enacted by or exist under Acts of the Parliament of Great Britain or of the Parliament of the United Kingdom of Great Britain and Ireland,) to be repealed, abolished, or altered by the Parliament of Canada, or by the Legislature of the respective Province, according to the Authority of the Parliament or of that Legislature under this Act.
The aforementioned provision from the Constitution Act, 1867 doesn’t mention the common law by name, but we know that the common law was already in place in those provinces (though Canada West/Lower Canada used Parisian customary law for civil law and in 1866 adopted a Civil Code similar to the French one to replace the former). British statutes are mentioned as well, and in fact excluded from being repealed or altered by the Canadian parliament (though this provision was rendered invalid by the Statute of Westminster, 1931). The common law would have been received into the union by those provinces by virtue of the phrase “all Laws in force in Canada**, Nova Scotia, or New Brunswick” .
** In this instance, “Canada” doesn’t mean the new union (though it does mean that in the reference lower down to the Parliament of Canada), but rather the Province of Canada consisting of the formerly separate Provinces of Upper and Lower Canada, now principally called Canada East and Canada West and severed by this same Act to become Ontario and Quebec respectively.
My personal opinion of the common law system is that, while it does have the added complexity of having to research precedents, is an essentially sound system, The whole precedent thing has one advantage, namely that older rules can be re-interpreted by courts as society becomes more progressive. Also, jurisdictions using the common law system now have extensive statute law as well, and statutory provisions that conflict with any rule of common law automatically repeal that rule of common law. Moreover, many jurisdictions have codified some rules from the common law into their statute law. For example, the California Civil Code (not a “civil code” in the continental European tradition of the French, Louisiana, Puerto Rico or Quebec Civil Code but rather one of the 29 codes that generally consolidate California’s statute law by subject) has many rules that were taken directly from the common law. So does (as far as I can tell) the Family Code, which was separated from the Civil Code in 1994. Of course, even statute law is subject to the rule of precedent in that courts render interpretations of some of them.
On a note related to the last point above, even in France, for example, judicature (IE the body of court decisions) is used by judges to interpret the law. It may not be binding precedent, but it certainly is persuasive (i.e. likely to be used and followed in future court decisions).