I find these arguments a little tired. The real difference between the two is simply that Ignatieff was a political naif, and his ego prevented him from doing certain work that needed doing.
On policy, his party always took the idiot-bait from Harper (e.g.: would have opposed c51 with mulcair on moral principle despite 80+% support across the country). The entire 2011 election was about how the CPC government failed to provide some report on f35 costing to parliament and was found in contempt of parliament and democracy itself. yawn. Letting Harper frame the debate on something Harper is strong at, is one thing. Trying to force people to stop caring about, jobs and the economy, and start caring about the sanctity of democracy is flat out naive.
Trudeau doesn't take the idiot bait. He also has a quite broad team from across the country.
One popular academical text on political persuasion holds that there is no such thing as a knock-out punch when you have two well funded competent candidates. It's a tug-of-war. But in Ignatieff we saw someone who repeatedly let go of the rope. For me most notably was on tout le monde en parle wherein he utterly failed to persuade anyone he represented QC values. This combined with Layton's remarkably effective performance kicked off the 'orange wave' right before easter-weekend, where everyone talked it over with their families and decided to vote NDP in QC.
That might have been salvageable if he had at least done his debate prep in English. The NDP had an advertising and social-media campaign set to go as a follow up to 3 possible 'zingers', and the likely responses Ignatieff had for each in the English debate. Not only did Layton land their zingers, but due to doing no debate prep in English, Ignatieff had a deer in the headlights response to 'If you don't show up to work, you don't get a promotion'. Egotism lost him a couple dozen seats in ontario that night.
Trudeau works his opponents to death. Just like Obama's team actually (think Hilary banking on super-tuesday and ignoring the caucus states...) For all the focus on his pretty hair, he won papineau by knocking on more doors, and making more personal relationships than any other candidate did. Same thing for LPC leadership. His work ethic will prevent him from skipping debate prep.
tldr: politics isn't a game for amateurs.