EDIT: I've just completed the retagging of questions about Sanderson and his works. In future, please use the brandon-sanderson tag only for questions about the author, and individual work tags, along with cosmere if the work is part of the Cosmere, as described here.
I recently posted a question
here on meta in order to try to pin down what tagging policy we should be following for the works of Brandon Sanderson. The consensus
there was that we should be using brandon-sanderson
only for questions about the author himself and using cosmere
as the franchise tag covering all his works (which is roughly what brandon-sanderson
being used for).
We still need to sort out the tagging of the existing questions, of course. This will be done by making a list of which questions are sufficiently author-oriented to merit the brandon-sanderson tag, then merging that tag into cosmere and re-adding it manually to those few questions. This task is high up on my to-do list, and I'll start on it as soon as I've finished sorting out the author-ID tag.
In the meantime, I'll make the user who's been suggesting those edits aware of the above-linked meta post about Sanderson tags, and ask them to hold off on further such edits until the time comes to properly sort out the brandon-sanderson and cosmere tags (at which point, of course, they'll be very welcome to help with the necessary retagging).
TL;DR: let's all hold off on Sanderson retagging until we know exactly what needs to be done.