I was particularly eager to see it because the source material is Friedrich Durrenmatt's play, "The Visit," which I loved when we read it back in 11th grade English. I also read it in the original German ("Die Besuch der Alten Dame") the next year.
The story was kept more or less intact in the translation to a musical. There were changes (no caged panther, rhyming names used only for the bodyguards instead of all of Claire Zachanassian's male attendants, etc.) but the basic plot was retained. The new yellow shoes (which were the subject of much merriment in my high school days) were the source of a major production number and an effective end to the first act.
The biggest change, of course, was the transformation to a musical. I think Kander & Ebb did a good job of creating songs that illuminate the characters. That isn't always pleasant, as the eunuchs describe their history in "Testimony," a song which is a good reason to keep anyone younger than, say, 14 from seeing this show. The choreography (by Anne Reinking) was also effective, particularly on this intimate stage with simple sets. But what really made the show for me was the performances. Chita Rivera (as Claire Zachanassian) is riveting. Her performances in numbers like "I Walk Away," "I Would Never Leave You," and, especially, "Winter" had everyone absorbed. George Hearn (as Anton Schell) has as powerful a voice as ever. Both of these Broadway luminaries have aged well. I also have to give a nod to Jeremy Webb as the Schoolmaster. Several of the people with smaller roles are notable for their dancing, especially Brian O'Brien (as Kurt) and Mary Ann Lamb (as young Claire).
Should this go to Broadway? My fear is that there would be the temptation to add too much spectacle, which would be very much the wrong thing to do with this material. There is both room for and need for less showy intimate musicals which emphasize character. I'd prefer to see this stay at its proper scale.