I actually think a number of 1776's melodies are quite beautiful, even magnificent. Thinking of "Cool, Cool, Men", "He Plays the Violin", and "Momma Look Sharp". As usual, it's the lyrics that really seem amateur at times. ("Sit down, John/ Sit down, John/ Oh for God's sake, John/ Sit down!") Still, that damn show packs an emotional wallop by the end that is inescapable and much more than the sum of its parts.
RAGTIME is one of the all-time greats of the musical cannon, but I'm not sure it qualifies as a true American history. Though it's peppered with real life celebrities, all the major characters are fictional, much like those in Les Miz. Both are set amidst real events but are hardly slices of history.