But as the nine candidates take their places on stage, it's got to be a source of comfort for Liberals that some of the pitfalls of their last two races aren't about to be repeated .
No matter how many people say this is Justin Trudeau's race to lose, at least he's running against a full field, and not against just one other marginal candidate, as Paul Martin did in 2003, winning almost 94 per cent of the vote, against Sheila Copps' six per cent.
And, in the 2006 leadership contest, the charge against the array of candidates was that six out of the eight of them were from Toronto, and that there was only one woman. (Other women candidates withdrew).
This time, there are three candidates from Quebec, as well as one from the West. It is also a historic first in any federal leadership race that four of the candidates are women.
There are no oddballs, or extremely fringe candidates, something the $75,000 non-refundable entry fee might have helped avoid.
All the candidates, even the relatively unknown ones, are accomplished in their various fields and fluently bilingual. Besides MPs and former MPs, there are lawyers and a retired air force colonel.
One Quebec political strategist noted, "All of them are much better than some NDP MPs from Quebec." He added that it's possible that the large field of decent candidates the Liberal Party attracted might "raise the Liberal brand."
Some candidates haven't finalized positions yet
Most observers don't expect much policy talk during the debate due to the logistics of allotting equal time to nine people, and some of the candidates haven't even formulated their final positions.
Someone close to the Trudeau team said Trudeau won't articulate so much policy as a message of hope. It's an "Obamaesque" strategy, aiming at the public's disillusion with politicians. A Liberal strategist said there's a feeling that Trudeau doesn't have to take risks about policy until he's leader.
On some of the themes for Sunday's debate, such as foreign ownership and Pacific Rim trades, there is an opportunity for candidates to put down markers. Both MP Marc Garneau and Trudeau have made statements, or speeches, about the importance of relationship with Asia, and specifically China. Before he entered the race, former MP and cabinet minister Martin Cauchon was responsible for his law firm's China strategy.
Another theme is electoral co-operation. MP Joyce Murray has advocated that Liberals, New Democrats and Greens consider run-off nominations to choose a single candidate in tightly contested ridings in order to defeat the Harper government.
Environment is another theme. Both Deborah Coyne and former Martha Hall Findlay are in favour of a carbon tax, or carbon "price."
Although Liberals profess to be excited about the diverse range of candidates, it may be hard to generate sparks for an audience. One of the complaints about the NDP leadership debates was that the candidates almost always agreed with each other.
But confrontations can "come back to haunt you," former MP Paul Szabo said. In the 2006 debate, Michael Ignatieff seemed to chide Stéphane Dion about his record as environment minister, repeating, "We didn't get it done." Dion, visibly upset, responded, "That's not fair ... Do you think it's easy to make priorities?" When Dion became leader, the Conservatives used that line against him in attack ads.
"Lessons were learned," Szabo said, adding that the candidates must balance their desire to be successful in the debates against the likelihood that they could damage the eventual leader.
The other candidates are David Bertschi, Karen McCrimmon and George Takach.
CBC News Network and cbc.ca are planning to carry the debate live between 4 p.m. and 6 p.m. ET.