How do you all feel about the idea the Emperor was nice to some Primarchs and a jersey to others to lay the ground work for a Thunder Warrior style purge?

I heard that there was a conversation with Malcador during the Siege of Terra novels where he mentioned some of the Primarchs rebelling was always the plan. But Chaos sped up the process and (I think) that some Primarchs rebelled when they shouldn't have and vice versa.

It makes sense to me that Konrad Curze was planned to rebel. Maybe even the Khan. Essentially, it was a way to purge the Primarchs and Legions too warlike to be useful post Great Crusade.

Imperial Fists, Blood Angel's, Ultramarine, and Salamanders feel most likely to be aimed at loyalty. While the Thousand Sons, Death Guard, World Eaters, and Nightlords seem towards treason.

I think the Flesh Change and plan for Magnus to be on the Golden Throne works as a way to quietly purge the Thousand Sons and get rid of Magnus akin to the two lost Primarchs. Maybe justify that Magnus is just a "machine

What do you all think?