KnowTheToe said:
You're supposed to be gone for three weeks
I feel it is a legitimate D&D product such as OA.
Yeah, so it was three weeks after all, shoo shoo be gone!!! (just joking, of course!

)
As for midnight, it is not different than D&D, it uses the D&D core rules as a base and subsidiary, enough that the PHB is needed for character creation and the other books in the usual manner.
I lost my answer due to lack of energy, but I summarised here:
Races and Classes: The changes are normal for a setting that has specifics of its own, Dragonlance and Forgotten Realms have entirely new races, Oriental Adventures has new classes and disconsider others.
CLeric, Spells and Midnight: This is the place that midnight is changed the most from D&D, but spells are kept the same, the casting works the same way, the system for gaining and stating how much spells you can cast are the difference, but it cannot be considered too far from elements of magic, for that matter.
UA and Midnight: I am not familiar on how UA is or works, I know it has a completely different approach to spell system, races and classes, maybe if I knew why it was under the OGL & D20 forum I would understand why midnight is being put there...
Anyway I also think midnight is mostly a setting, while UA is mostly a new D&D approach, maybe I am wrong, but would want to know why the moderators think midnight is enough different to be put under the oted forum and not under general. What makes midnight not D&D but something else that is not true for FR, OA and other D&D settings that are not the default?