As putschs go, this one is pretty pathetic - for three reasons.
1. The Demand: It makes absolutely no sense for Harper to step down now. Yes, I know I said it would be in the best interest of the CPC if he resigned back in June, but that was then. Parliament will be opening in two weeks and there isn't time for the Conservatives to find a new leader before the next election. More importantly, it only makes sense to call for a leader to resign if you think there's a chance he will actually do so. Harper didn't step down over the summer so it's obvious that, rightly or wrongly, he's resolved to lead the Conservatives in the next election. Since Harper will stay on, public comments like this can only hurt the Party and have zero chance of accomplishing any good.
2. The Messengers: The four behind this admit they didn't support Harper for leadership so already this shouldn't be seen as a bold statement on their part. After all, 16% of the party voted against him in leadership review so it's not a miracle that four of those members stepped forward. Lucien Richard garnered a whooping 8% of the vote last election, slightly ahead of Payam Eslami's 6%, good for a fourth place finish. And I'm going to go out on a limb and guess that Monsieur Remillard won't do much better. The fact is, these are people the Conservatives have put up as candidates in sacrificial ridings. If the CPC in Quebec is the same as the Liberal Party in Alberta, I imagine anyone who wants a nomination in a riding like that, gets it. If the Liberal candidates in Crowfoot, Macleod, and Peace River came out demanding Paul Martin resign, it would mean absolutely nothing. People who run in ridings like this aren't necessarily "key" members of the party.
3. The Message: To make matters worse, their letter isn't overly convincing. They claim that the Liberals would win a majority government under current conditions, bringing to five the number of Canadians who believe this (David Herle being the other one). They say that "we will never win the next election" and I wouldn't even be certain of that.
I'm not a fan of Harper and it likely would be in the best interest of his party if they had someone else leading them. But no one should put any stock into a letter from four nobodies in the CPC.