Although your examinations of some of the "backbone" of this film could be called "juvenile"...I compliment you on your dissection.
More to the point, I would agree on a number of points as to quality of performances. Most specifically Spacey, a talent of depth, ease and range, unparalleled excellence.

The only dilemma I have with calling anything "the best ever" is that it alienates everything else. I have favorite films, films I loathe, films that are superior to others, films I treasure...but not a "Best Film".