These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
True Art Is Angsty: Though many early critics and Gilbert himself thought Sullivan's ghost music in Act II too heavy and serious for a comic opera, modern musicologists have come to regard it as some of the finest Sir Arthur ever composed.
Vindicated by History: Ruddigore didn't do too well at its initial run but this was mostly because The Mikado was a very tough act to follow. However the work did enjoy some success later in the run. Unfortunately it was either never or else hardly ever revived during Gilbert's life time. It was however restored to the canon in the 1920s where it has remained ever since, and if anything it has grown in popularity since the close of the D'Oyly Carte company.