I actually can’t stand hyper-real, “vivid” world-building. Leiber names maybe at most a dozen streets in Lankhmar and describes less than half a dozen neighborhoods — I’d be surprised if he mentions more than four neighborhoods.
However I realize I am in the minority with this opinion and wonder if the clotheshorse swordporn I hate so much might stem from audience overlap with the SCA that values that level of immersion.
Remember Lucas’s Law: The Clone Wars were so much better imagined than seen. The job is to write stuff wide enough for the reader or player to get lost in and shape on their own, than to shape it all for them and suck the life out of it.
(from an email discussion with some friends)