The last time I heard this story I was left with a completely different impression.
The narrative showed that certain events are destined to happen, but the events leading up to them or the conclusion is not set in stone.
As long as the cards are played right, the victory at only those events are necessary to guarantee an overall favorable result.
Malcador was of the opposite mind initially, where he wanted to ensure victories all along the way. This is the ideal scenario the Malcador wishes for the Imperium to pursue.
He was shown that there are enough wildcards around that the only guarantee they can have are those critical events and it was better to let the whole thing unfold along a more predictable line.
Malcador feels dejected at this but is shown that his IS a much needed hand in the events even if it feels like his words are not heeded.
The story ends with the breaching of the warp veil by the traitor fleet that has finally reached the Sol system (A critical Event).
Malcador is left alone as the Emperor goes to take his role but not before reminding Malcador the role he has chosen of his own accord.
My memory may not be wholly accurate about this.
Edited by Nashnir, 14 March 2019 - 07:58 PM.