Many jurisdictions are introducing SLAAP reforms. Ontario is currently considering recommended reforms.
Beyond that Law Societies have the power to discipline lawyers that bring frivolous cases that are a abuse of the process. Those complaints should be made more often, because the Codes of Conduct already have the rules in place.
http://www.lawsociety.ab.ca/docs/def...3.pdf?sfvrsn=2
4.01 (2)
When acting as an advocate, a lawyer must not:
(a) abuse the process of the tribunal by instituting or prosecuting proceedings that, although legal in themselves, are clearly motivated by malice on the part of the client and are brought solely for the purpose of injuring the other party;
(b) take any step in the representation of a client that is clearly without merit;
(c) unreasonably delay the process of the tribunal;
(d) knowingly assist or permit a client to do anything that the lawyer considers to be dishonest or dishonourable;