Since television series tend to emphasize continuing character over plot, I'd say leave a poor idea alone and base musicals on books, plays or even film scripts. These properties have (or ought to have) a beginning, middle and an end.
The shows might even work provided they are adaptations and not verbatim translations i.e. Saturday Night Fever or Urban Cowboy and even Billy Elliot.
Plot is always the failing point of tv shows adapted to other mediums.
"If my life weren't funny, it would just be true. And that would be unacceptable."
--Carrie Fisher