Sadly, there hasn't been much restorative-based work carried out at Canada's best pre-WWII golf courses; and, in my opinion, our country has quite a few good ones from this era which possess some serious potential for improvement through some restorative-based work.
My friend, Rob Thompson, has an interesting list of "Top Six Canadian Courses that should be Restored" posted at his blog today. Check it out here:
http://www.ontgolf.ca/g4g/Rob's choices are good.
His no. 1, Hamilton, is a great choice. It wouldn't take much - adjustment to grass lines, restyling the bunkers, some tree work - to make Hamilton a genuine world top-50 golf course. Colt's routing, over a wonderful piece of ground, is excellent and basically still intact; though, there's a tremednous opportunity to restore Colt's 15th and 16th holes, which would markedly improve the course.
Basically intact as well, Colt's 15th green is currently used for the first hole on the Robbie Robinson-designed nine holes there, at Hamilton.
Off the top of my head, I'd add the following "high-profile" Canadian courses to Rob's list: Royal Colwood (Vernon Macan); Capilano (Stanley Thompson); and Toronto Golf Club (Harry Colt), which is Canada's "National Golf Links". In other words, Colt's design at Toronto revolutionized the Canadian golfing landscape, setting a new standard.
It should be noted, too, that some interesting restorative-based work has been carried out recently at Essex (Donald Ross/Renaissance Golf) and Calgary Golf (Willie Park Jnr./Ron Forse). And, I have a CLASSIC consulting report written by Rod Whitman for Mayfair, in Edmonton, that was never utilized by the club. This document is a treasure!