Let me begin by saying that I can't stand Harper, and would love to see him and the Conservatives taken out of power. That being said...
...I think there's an awful lot of partisan hyperbole here. There are no indications whatsoever that this was part of a national strategy, or that the party leadership either knew about or endorsed such actions. It seems much more likely to me to be the result of actions by local idiots, without the knowledge or permission of the party leadership.
In addition, while such tactics are shameful, they don't seem to have had any significant impact on the actual results (in Hamilton, where the most serious case seems to have been, the Liberals won by quite a significant margin). There is no evidence whatsoever that there's anyone who won a seat fraudulently.
Harper absolutely should have called for an independent investigation immediately; and some of his nonsense (such as insisting that Liberals should make all information about who they called public, but saying that the Conservatives don't need to) really goes beyond acceptable. But that's just the way the man is...he's a control freak who does everything he can to ensure that any information related to his own party is thoroughly controlled by him. (Witness the current debate over federally funded science research being controlled by the Conservatives, with scientists unable to comment publicly or publish their research without first being vetted by the gov't). I don't think it is so much an effort to cover up something he did, as it is to maintain control over information that he's unsure what actually happened (and doesn't want others getting that info before him).
A few isolated cases of attempts at fraud, that seem to have been carried out by individuals without knowledge of the party leadership, that had minimal or no overall impact on actual election results.
It is, to me, not so much an indication of problems in Canada's system, as it is an indication of just how well controlled and monitored our elections are that this is the biggest scandal facing us. In the U.S., there were scandals that literally impacted who finally got chosen as the President of the country...that's major. In Canada, we've got small local elections where the aggrieved party still won by a significant majority.
Absolutely, this needs to be investigated. Absolutely, those responsible need to be identified, and punished.
But let's keep some perspective here, folks. As far as voting scandals go, in most countries, this wouldn't even register as mildly unusual.
ETA: And can we please get rid of Harper?!?