Most of these "classics" were used for SWs in a rather superficial way.
Where is the sense to adopt Romeo And Juliet without using the end?
Hamlet is full of doubts and hesitates, one of the the play's main elements, but Johnny Hamlet has never any doubts about what he is doing.
And besides removed from Shakespeare's dialogues the pure stories are rather simple and old-fashioned from a modern point of view, and at least the screenplaywriters adapted them very loosely, in the end so loosely that I always wondered why they actually did it in the first place.
I don't know very much about Orestes, but it seems In The Forgotten Pistolero also only the bare structure was used, the outward story, and they left all away what the play was about.
At least they used in all these mostly only a few plot elements which didn't tell them apart from other SWs. Only Johnny Hamlet uses more of the play's ideas for several parts of the films, sometimes in a rather odd way, sometimes out of the play's context and also out of the film's structure (Ophelia in the river).
Don't missunderstand me, they aren't bad films, it's only the fact that they used the classic plays doesn't made these films better or worser. I think this all is interesting only in a way that justifies not much more than a bare mentioning.