Not a riddle but if you can your help will be appreaciated, I tried all the obvious answeres.
"Two newspaper editors are arguing about how to arrange a layout. They're happy with the photos they have, but the text itself needed spicing-up. They were looking for a more in-depth analysis than the one they had written already. One of them says to the other, You know, we should ask Jenkins. He's a proper _____, I bet he could give us some ideas."
not that I can see how cruciverbalists provide more in-depth analysis, though they are fine people. The question's not actually very clear; providing more analysis isn't the same as being good with words.
If he buys a newspaper for his lunch break and its not to read it, it's likely he's doing the crossword. That would also fit in with someone who is good with words.