As long as the Liberals significantly improve on their 2011 results and there is no Conservative majority, Trudeau's job as leader is secure. If the Liberals are still in opposition, they can present thenselves as the principled and moderate opposition while the Conservatives are waging their civil war (a formal split of the Conservative Party won't happen, as everyone knows the right will be shut out of power for a generation).
By 2023, the NDP will probably have become tired. Trudeau himself will have significantly aged, and physically seems more mature. In any case, by then anyone refusing to vote Liberal due to their bad memories of Pierre will be in their 70s. This puts him in a great position to decisively win. And, unless the Conservatives win back their lost support this year, Harper's unpopularity will haunt them for many years to come. This final point is predictable. How do the Ontario Liberals hold power other than using the bad memories of Bob Rae and his successor?
Yeah, but by 2023, a tsunami could have wiped Nova Scotia away and loons could have evolved laser beam-shooting eyes.