This is a huge issue. Especially coupled with the rise of the NDP, and the collapse of the Liberal party. I don't think it will get any better either, as it seems like the NDP are going to be popular from now on, and the Liberals just elected Canadian royalty to be there leader. I think it's time to seriously consider a coalition government, especially if the Cons are able to get a minority gov't again. Coalition governments are a staple in many European countries. Neither of the two parties ( libs and NDP) have really been open to the idea yet, but I think they need to just try harder. As you said, they both lean left, no reason why they can't lead this country together.
Just so I'm clear, I'm talking post election, and only if it looks like the Cons are going to retain power. I don't think the NDP and Liberals should merge right now.
Other than that, I got to meet Justin Trudeau on PEI and have great hopes for a resurgence of the Liberal party in the next election.