On the Process of Interpretation in Music - Two Words with the same meaning?

For me, the word 'opinion' is simply another word for 'interpretation,' when the issue of the ways of dealing with the core meaning of a composition is addressed. To enter into an attempt to explain:
It seems, in general conversation, that more times than once I encounter the impression on the part of some that continues to persist when the name Toscanini is raised.
There continues to exist a premise that the universally known tyranny of the legendary conductor was the result of his insistence that the interpretation of a composer must come to rest in totality upon the composer's  own view of  that piece. And, on the surface it seemingly makes sense as to the magnificent intransigence of Arturo Toscanini, in what is known about the countless examples of  those fearful fits of temper he flung out to the unfortunates who dared to veer off the road during rehearsals.
But, in listening to recordings of the same composition by Toscanini (which are available), one will note a difference of opinion by Toscanini himself as he travels from one period in his lengthy career to another.
First of all, how many of us  were THERE at the creation of a Beethoven symphony or a Mozart concerto? How is it possible to know what were precisely the whims of the composer in his view of that masterpiece, and at that time? And; secondly,  the composer himself may well  alter his views about a given creation as a normal  part of that process we call 'growth.'
I recall that telegram sent by the composer Prokofiev to the pianist Horowitz during the Second World War after hearing the great Russian virtuoso's performance of  one of the so-called "war" sonatas that Prokofiev had written: "my congratulations to the great pianist who found more in my music than I  did(had)."
Great art, in no matter what form, has no bottom, no top. One can only speculate as to the whim of the composer. The performances that to me are 'great' are those I recognize as those given us by the performer who has an  impressive level of   contact with the historical context, the genius of the writer, and the ability to project at a high level.
What comes to mind is what the Spanish violinist Ricardo Odriozola projects in his liner notes in a Bach album he released not too long ago - without a trace of ego, Odriozola  discusses his contact with the composer as being of relevance and import, in describing his contribution to the recorded works of the Baroque legend. Do listen, and see  if you agree with my opinion that there is much said.
What, in your opinion, does the word 'great' mean to you, as you listen to the music of your choice?