Stephane Dion is just a tiny blip on the history of the Liberal Party. His most notable accomplishment was "The Clarity Act". It is supposed to be a clear guideline of how the question should be asked, should Quebec separatists decide to hold another referendum. Just like Stephane Dion's hopes of becoming Prime Minister, hopefully there will never be a need to apply this legislation.
Michael Ignatieff has brought an immediate change of course to the Liberal Party. He has announced that the Green Party will not get any kind of free ride from the Liberals in the next election. He believes the environment plank of their platform will be able to stand on it's own. He also acknowledged that the Alberta Oil sands are an important part of the Canadian economy. He will not alienate Western Canada. This a change from Dion who tried to make them the major target of his environmental plan.
Ignatieff has earned respect from Harper because he is willing to stand up to the government if ti is the right thing to do. This change of course continues to take the Liberal Party on the path as being a viable alternative to lead the country. Governments are more in tuned with the public, when they are battling to keep their jobs. A strong Liberal Party is good for Canada whether they are in the government or sitting on the opposition benches.