Just some examples:
* That strings bit leading into "Worst Pies in London" after the second "Hole in the world..." 'speech' has always sounded to me like it could benefit from being played on electric guitar.
* I think the "Ballad" sequences could also sound interesting, in a piano/bass/drums type set-up. They already have a sort of groove, and I think stripped down slightly it might be worth a listen.
* "Green Finch and Linnet Bird" might sound interesting as an acoustic pop type thing, like "Blackbird" by the Beatles, a total 180 from the usual arrangement, more restrained. She yearns to fly but still something holds her back. Dramatically speaking, that's how the number has always felt to me anyway, only to see Betsy Joslyn's performance on the 1982 DVD and react with utter friggin' dismay.
* "Epiphany" would work as a total eruption a la Steinman/Meat Loaf.
The key is that you don't throw every rock element at every song; that's just ridiculous. You find the common sound in rock music and in the source material and utilize that. To reverse Mercedes McCambridge's quote on acting, "Don't just utilize, analyze beforehand."
"There is no problem so big that it cannot be run away from."
~ Charles M. Schulz