Yeah, I know. I'm just saying that the one (long-term planning) isn't strictly indicative of the other (Stellar authorship).

We haven't really had long-term planning and foreshadowing in the past, but that's probably because Halo was written under multiple independent authors, and Bungie's plans were ruined by Halo 2's development hell.

: Or maybe an alternate method could've been used to get rid of
: Requiem, if the planet being destroyed was planned years in advance
: (without deep specifics on how).

The problem with Requiem being destroyed is that it was an incredibly powerful resource that Jul 'Mdama threw away for no conceivable gain. If Requiem was really the fortress-world from which the Didact intended to defeat the Flood, surely it would have had the automated factories needed to produce warships, weapons, and combat drones. If the Librarian decommissioned those factories on her way out, she would have had to leave some intact so Requiem can repair and maintain itself.

What could Jul 'Mdama accomplish with a swarm of repair sentinels tens of millions strong? What if he used Requiem's factories to turn out hulls with Forerunner shields and power sources?

So, even if the self destruct option had been foreshadowed in prior fiction, it would still have been a crappy plot turn.