I would be surprised, yes.
No Dragonlance books appear in the
top 100 at Amazon for science fiction and fantasy. (Van Richten's Guide is at #15.) Nor is it in the
top 100 for Amazon for just the fantasy books. (Incidentally, all the people freaking out about how D&D doesn't just include what fantasy fiction included in 1979 would do well to look over the diversity of these lists and how much fantasy has changed and expanded. D&D is just following audience tastes and reflecting the influences modern game writers bring to the books.)
I am not convinced the DMG -- and core books generally -- don't already cover this adequately. What epic fantasy elements aren't already mechanically supported in 5E?
But he didn't really put it in Greyhawk. This is the guy who attacked his players with a Panzer tank driven by Nazis and published two modules based on Lewis Carroll. The Greyhawk folio had a high medieval knight on the cover and heraldry for all of the major nations. The "Greyhawk = sword and sorcery" thing people have been advocating for the last few years is ahistorical at worst, or based on Greyhawk Wars exclusively at best.
I'm also not sure WotC wouldn't just roll Greyhawk back to the original boxed set era for a nostalgia-driven 50th anniversary publication, which would strip away almost all of the sword and sorcery stuff.
And, in any case, what mechanical support is needed to make 5E more sword and sorcery than it already can be? Ravenloft and Theros added mechanical elements that supported their themes, but other than listing a price for chariots, sandals and chainmail bikinis, what is 5E missing for sword and sorcery?