Don't most pianists tend to conform to the prevalent understanding of how a piece is played?
Only the ones wasting their (and everyone else's) time playing it.
On your original question, Chopin uses 4 different tempi for his Polonaises - Maestoso, Allegro Maestoso, Allegro ma non troppo and Allegro. Maestoso is more a mood than a tempo, but it's at the very slow end of Allegro in this context, and whilst it changes subtly through the piece, the basic tempo doesn't alter much - no change is indicated by Chopin (except appassionata at some point).