I'm confused. How are Sondheim and Caroline similar? I can understand not enjoying Caroline because most of it is not really melodic, but which Sondheim shows are the "talking music"? The majority of Sondheim scores are quite melodic, memorable and include many standards that are frequently sung outside the context of the shows.
Most of Into the Woods, Anyone Can Whistle, Follies, Forum, Company and A Little Night Music are pretty standard melodic showtunes. Passion and Sweeney are really his only shows that feature much recitative (sung dialogue). Assassins, Bounce, Sunday and Pacific Overtures are probably his most unusual scores, but they still have some stand-alone songs. I'm not familiar with the new Frogs score, but I do feel the old score was not memorable.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian