Some plays are so inherently theatrical and, their theatricality so definitely a part of their success, that I would rather see a literal filmed transcription of the play as opposed to seeing it made into a "movie".
Examples that come to mind: MAN OF LA MANCHA, THE FANTASTIKS, ROYAL HUNT OF THE SUN (despite a mesmerising performance by Christopher Plummer and an earnest attempt). I think the SWEENEY TODD film also fails, truncated songs, not great singers, and a languidness about it. I'd much rather watch the Hearn /Lansbury taped theatre production.
Stage farces rarely work on the screen FLEA IN HER EAR and NOISES OFF come to mind. The amazement with these kind of shows comes from all the door-slamming and physical timing onstage. Though two film farces that I think do work would be ARSENIC & OLD LACE and THE RITZ. Of course, I never saw The Ritz onstage; and I only saw Arsenic onstage after I'd seen the film.