Okay, so I liked this performance a lot. Tsujii played Rachmaninov's Second Piano Concerto, and played it well from the opening chords, to which he applied a judicious gradual crescendo. He showed a good command of the idiom for a non-Russian player, his virtuoso runs in the second movement were nicely shaped, and he was emotionally direct in the famous theme from the third movement. The whole piece was taken a bit too slow, but I think this might be more on the conductor than the pianist. The soloist is supposed to push the tempo if the conductor is dawdling, but I'm not sure how the whole Japanese thing of deferring to one's elders might have come into play. I didn't get the chance to see the live concerto rehearsal footage on the web, so I don't know how Tsujii's relationship with Conlon played out. Perhaps someone who did watch it can enlighten me.
All in all, my theory that Tsujii is better in an ensemble than by himself is looking pretty good. I still think that his solo performances didn't merit advancement, but because the judges advanced him through the rounds anyway, he was able to show me strengths that I wouldn't have guessed at. It looks like the judges knew his capabilities better than I did. (Then again, they're supposed to.) I've made my peace with this pianist being in the finals. Let's see how the rest of the round unfolds.