To those whom it may concern:
This video provides a view of Sector 6 from the Sector 5 slums. As you can see below, Sector 6 is fully intact, despite the fact the plate collapsed over two decades earlier in [μ]–εγλ Circa 1976.
Though, in the interest of fairness, it should be noted that the original Crisis Core has this same inconsistency. Here's the view from the same cutscene:
Update: The below paragraph is wrong. The collapsed Sector 6 skybox is also used for the extra missions.
This intact Sector 6 plate is consistent with the skybox used for Midgar in Crisis Core Reunion's extra missions, which I managed to find a good look at in
DevilNeverCry's review for the game (screenshots in the spoiler tag). It would appear that all of Midgar's plates are complete. Keep in mind that the game's extra missions may take place anywhere in the slums, so I imagine they only made one skybox to be used for all of them. It may be that they omitted the collapsed plate because it could've been used as a reference point, consequently creating inconsistencies with the mission description. Or they just forgot...
But wait, there's more~
In Reunion's pre-release screenshots, we can actually see the collapsed Sector 6 skybox in use over Evergreen Park. Will this make it to the final game? Or has it been replaced with the complete Midgar skybox seen above? And here I thought the
Buster Sword would be the only quantum state issue...