Zerebos said: I've seen an Okuu one from a different artist though. As well as a Patchouli and Iku, and even Mami Tomoe.
That's like saying glasses girls are becoming a trend meme. The sweater fetish is just that, a fetish. Not exactly a trend or anything. It just means more than 1 artists have the same taste in fetish. ogami_kazuki certainly isn't the only artists to always have a glasses version for all his art for example.