First thought: Holy Smokes he has Sodor!
Second thought: Holy Smokes he has Thra!
Third thought: Wait, he has Terabithia as a real place?
Since I'm unsure if anyone's done it before, I might as well list the origin of the lands for those who don't know:
Avalon - Island of Arthurian legend (don't know why he's put Camelot there, am I forgetting a series that did this?)
Dinotopia - setting of James Gurney's Dinotopia
Dreamlands - setting of H.P. Lovecraft's Dream Cycle
Earthsea - setting of Ursula K. le Guin's Earthsea cycle
Florin - setting of William Goldman's The Princess Bride
Hyrule - setting of the Legend of Zelda games
Kadath - see Dreamlands
Krull - setting of the eponymous 1983 film
Labyrinth - setting of the eponymous 1986 film
Land of the Lost - setting of the eponymous 1974 series
Lidsville - setting of the eponymous 1971 series
Lilliput - one of the islands of Jonathan Swift's Gulliver's Travels
Living Island - setting of H.R. Pufnstuf
Middle-earth - setting of J.R.R. Tolkien's The Hobbit and The Lord of the Rings
Moomin Valley - setting of Tove Jansson's Moomin novels
Narnia - setting of C.S. Lewis' The Chronicles of Narnia
Nehwon - setting of Fritz Leiber's Fafhrd & the Gray Mouser stories
Never Neverland - setting of J.M. Barrie's Peter Pan
Oz - setting of Frank L. Baum's Oz novels
Sodor - setting of W.D. Audry's The Railway Series
Solla Sollew - setting of Dr. Seuss' I Had Trouble in Getting to Solla Sollew
Terabithia - setting of Katherine Paterson's Bridge to Terabithia
Thra - setting of The Dark Crystal
Westeros - setting of George R.R. Martin's A Song of Ice & Fire novels
Where the Wild Things Are - setting of the eponymous Maurice Sendak book
Wonderland - setting of Lewis Carroll's Alice books
Utopia - setting of Thomas More's eponymous novel
Of course, it's problematic: the inclusion of Middle-earth means that the Haradrim apparently dwell in Moomin Valley (suddenly the Mumakil make sense!), the Easterlings are rampaging through Wonderland, and the ruins of Beleriand are in Oz. Generally, I don't think it's a great idea to include any worlds that are meant to be earth in an ancient times: naturally, this would mean Middle-earth doesn't appear. This is a cool idea for worlds apart from ours, where one could possibly see them coexisting on some mass continent, preferably where only a few lands or kingdoms are detailed. I can imagine Oz, Narnia and Wonderland being neighbours. And, knowing me, they'd be going to war all the time. The Army of Oz allying with Narnia against the Queen of Hearts' invasion, perhaps?
A couple of people have commented: where's the Hyborian Age? Or, rather, "Hyperborea" and "Cimmeria," nobody seems to have mentioned the dreaded "Hyboria" yet. Well, I think it's as unsuitable as Middle-earth, for all the reasons I stated above. Assuming Dan's being geographically sound, even the part of the Hyborian continent Howard detailed would be the biggest part of the map - and then, what, would Vendhya be replaced with Terabithia? The only way I see this working is if the above is, in fact, The Nameless Continent - but then, that wouldn't work with "Marchers of Valhalla" and others.
So, I'm not bothered by the lack of the Hyborian Continent, even if I am somewhat bothered by the inclusion of Middle-earth. Nor any of the other lands which are set on our world in a different time in the past, like Smith's Hyperborea, or future, like Smith's Zothique. Some other worlds are simply too vast to include: the world of the Young Kingdoms, for instance. The inclusion of Fantasia (surely Fantastica, Dan?) is also, by its definition, the entire realm of human imagination - so, really, the entire world should be Fantastica. And then you have the likes of Discworld, which... well, it's hard to translate a disc spinning on four elephants surmounting a gargantuan turtle into such a map.
That said, I'm saddened by the lack of Prydain: it's based on Wales, so surely it could be snuck in somewhere. Amber, too, wouldn't be too hard to include. Nyumbani might be a tad massive (size of Africa, after all) but if we presume this was a particularly large planet, say twice or thrice the size of earth, it might still work.