Unfortunately, this is about as good as it gets if you want students to read myths (rather than reading ABOUT myths) and give them some cultural variety. The alternative for an instructor is putting together a prohibitively expensive reader, or requiring a whole list of books, or depending on students to read excerpts from books on library reserve (which they ordinarily won't do), or requiring other single-volume texts that are imperfect in their own ways. (Thury and DeVinney's "Introduction to Mythology," good as it is, is labyrinthine in its organization and would make my students leap off the nearest cliff; Roy Willis's "World Mythology" is all descriptions and summaries, with no narratives at all.)
This collection leaves much to be desired, though, and so do Rosenberg's interpretations. I'm not sure what her specialty is, but in many cases she relies on poor sources. For the Celtic material, for instance, she draws from reprints of 19th and early 20th century texts that are themselves inaccurate fairy-tale-style retellings of the actual texts. Her descriptions of Celtic belief are also grossly outdated: so far as we now know, the Celts were not sun worshippers and their major holidays were not at the solstices and equinoxes. Even the most cursory research would have led her to more accurate translations in scholarly journals, or she could have used the same sources that Gantz did for his much more accurate renditions of Irish myth in "Early Irish Myths and Sagas"--one of the many texts one would have to require in the multi-text syllabus.
Rosenberg is also enamored of the strain of thought that identifies every powerful goddess figure as a Great Goddess worshipped by the agricultural matriarchal societies of old, a type of society that no one has ever been able to show existed; even neo-pagans prefer the term "matrifocal," and most anthropologists and folklorists would argue even with that term. That leaves the question of whether Rosenberg's understanding of myth is late Victorian or New Agey or both, but it doesn't seem to be very scholarly.