I think Macbeth, Tempest, Merchant of Venice get done in low budget film because they can be done in some kind of 'contemporary' way that nullifies class distinctions and sands down the 'noble' traits of tragic or romantic heroes. Demotic mood does not do tragedy or lyricism well. Branagh can film those plays, but with lavish production values and actors who can shake off their contemporary slush-mouth and bad postures to make those characters walk, talk and breath rightly. What is rightly? In a way that we, the audience, can hear and see that these characters are our most essential selves animated; our most essential selves in the throes of our most essential conflicts. That takes bigness and myth done through small gesture and naturalistic grace notes as well through open-throated epic style.
Film CAN do bigness and myth for Shakespeare through very filmic performances--with much fluttery eye lashes and pouting--but not JUST with filmic fluttery pouting. Film Shakespeare still needs size. Not necessarily vocal size, but size of physical embodiment, articulation, emotional commitment, individual spirit, and capacity for seeing how the public and the private interpenetrate one another at very deep and subtle levels; the public and private are fibrously bonded in Shakespeare, and most contemporary actors available for low-budget film can't get close to conveying that. Big money for big actors solves the problem. But, is that interesting?
Oh, to be a Branagh, Nunn or Polansky.