The campaign was nearly flawless. Especially the decision to run to win. (Some of us have been advocating that for a while. It's usually gotten us accused of any number of thought crimes by people who advocate voting Liberal.)
Co-opting the Tory frame and flinging it back at them with a new kind of strong showed a new kind of seriousness.
Could have used Dion's support for the Tory corporate tax cuts as further evidence that the Liberals are just Conservatives.
Highly effective slap-down of Dion in the debate.
The one serious problem, I think, was candidate vetting (as statica has mentioned).
While one of these candidates (Durham) was a last minute filler, I understand, the other three were serious candidates, it seemed.
We may need to adapt a system as in the UK where the party heirarchy vets candidates before they are allowed to stand for a nomination.