surely one of the greatest Russian composers since Tchaikovsky
Hmmm, I saw what you did there ;)
Quite a few rather important composers have slipped through the cracks there, haven't they?
Both Taneyevs (although primarily Sergey), Rimsky-Korsakov, Gliere, Glazunov, Scriabin, Rachmaninov, Medtner, Prokofiev, and a chap called Stravinsky? Not to mention a host of piano-soloist-composers, and other composers from the non-Russian parts of the USSR, and even further afield.
I think there are strong grounds for naming Prokofiev as another worthy carrier of Tchaikovsky's mantle? He lovingly pastiches his beloved master in so many of his works, WAR & PEACE not being the least of them (which opens with a clear homage to THE QUEEN OF SPADES)
Of course in our house we are unrepentant evangelists and activists for both
and