If it were up to me I would want all reference to any world -- and especially the "D&D multiverse" -- excised from the core books. D&D is, to me, a tool kit for creating your own fantasy adventures and does not need setting info or lore baked in. The DMG could certainly include some examples in the world building section, though.Certain positions of privilege in the core rules.
If the multiverse is the default setting, do a better job of giving non-Realms examples. Especially Realms specific bullsh*t like "The Weave" that new players mistake for rules jargon.
The segregation of races into Tolkein fanservice "common races", and everything else as "uncommon". Stab it repeatedly, burn the body, and piss on its' ashes.