/home is somewhat of a system directory but sub directories within it probably contain the bulk of user data. If I wish to move non system material to a recently added drive, it can be done with various cp commands and a few mv commands to perform the substitution in the end. (mv /important /oldimportant; mv /newimportant /important).
Would there be anything different when attempting to mv /home /oldhome;mv /newhome /home In order to perform such a move, you've got to be using an ID on the system. All IDs on the system have a directory within /home from which configurations unique to each ID are referenced. That material is going to be in use when the move takes place.