I love criticising the actions and poor fathering skills of the emperor as much as any fan, but i thought it would be interesting to force myself into his shoes (admittedly with the power of hindsight) and think about how i would have done things differently.
First off, as soon as i found each primarch, i would tell them about my true origins, my god like status and the nature of the warp/gods. Alot of the traitor legions saw their betrayal as payback for what the emperor had done to them, his lies. I completely expect that even though i warn my sons, some will turn to chaos anyway, its inevitable. However i would argue that it would be a number fewer than half as happened in HH. for example, i dont think horus would have turned, as erebus wouldnt have been able to use the emperors lies (with a sprinkle of chaos influence) to shock and sway him. if horus doesnt turn, i think that alone would keep many of his brothers onside too.
before i move on from primachs, two things
1) i see no problem in putting legions down, as has been done. this would obviously come to pass as some would be tempted by chaos. It would be interesting to see (obviously we will never know) if characters such as angron/curze/fulgrim would turn to chaos with the info on their true nature, or whether they would simply be 'bad' of their own accord.
2) what to do with the word bearers ... i guess if i proclaim the emperor as a god like being, i would have to allow their worship. unless i explained that one can be a god without seeking or needing the worship of others. would they accept this ? probably not.
IF i were the emperor, i would stress the need for cooperation and unity among brothers as the greatest tool to fight and defend against the influence of chaos. sure some would still end up hating each other, but i think they would at least make an attempt to stand together.
would i keep chaos away from wider public knowledge .... i think yes. Humans are too inquisitive to be trusted with such information. there would be people experimenting and dabbling with things they cannot control. perhaps i would fabricate a heaven (emperor) vs hell (chaos, but over simplified) for the people to 'fear' to control them.
i have rambled on for too long, sorry if it was hard to read. I would love to hear what you guys would do if you were the emperor, lets say 'in any point in time' to make it interesting !