Complex sentence: Faivre's form of categorisation has been championed by scholars like Nicholas Goodrick-Clarke, and by 2007 Bogdan could note that Faivre's had become "the standard definition" of Western esotericism in use among scholars.
Split into simpler sentences: Faivre's form of categorisation has been championed by scholars like Nicholas Goodrick-Clarke. Bogdan noted that by 2007, Faivre's had become "the standard definition" of Western esotericism among scholars.