Doing a quick Google myself the instances of "variegated writer" seem to be mostly from several generations back, not recent. It sounds odd to me too.OK, I concede it does appear to exist 'out there', but I've not come across it before, and I wouldn't happily use it myself.
Or "versatile.""Variegated writer" does not occur often enough in books to show up in ngrams. "Multifaceted writer" does. I wonder if that would work for you.
Possibly. But you mean "multifaceted," not "multifaced."Would also "eclectic writer" work in his context? I can't really say whether there is a difference in meaning between eclectic and multifaced.
Yes, this is what I'd have meant, if only I were able to read properly!Possibly. But you mean "multifaceted," not "multifaced."