Precisely (and for a much better explanation, I (and I assume JamesS as well) would direct those interested to the interview between Gould and Tim Page on the "A State of Wonder" Goldberg collection. I think Gould does a fantastic job of explaining the tempo correlations in his musical style in layman's terms on the disc).
And I forgot to mention, for as little as it's worth, that for "Romantic" pianists I prefer Cziffra's technique, but I have always been strongly partial to Cziffra (him and Gould, heh). Michelangeli does some incredible things as well, speaking of technique as a vehicle for accurate and effective self-expression. Nobody could play the 4th Rachmaninoff concerto like him! And mechanically speaking, of course he was top-notch, if not on the same level of Cziffra and Gould and...all those other wizards.
Hamelin's technique, on the other hand, comes across as exactly the opposite for me. Mechanically, a better pianist than Hamelin is almost inconceivable. However, viewing his technique as a way of effectively portraying the music and its emotions...well, it's been said before but I admit that I also tend to find it dry and monotonous. I think his technique, as a supremely relaxed way of playing evenly and with the "best" and "perfect" piano tone, greatly limits his variety to the point of occassional boredom, depending on the piece I suppose. Cziffra's technique, on the other hand, enabled him to imbue all of his pieces effectively with adrenaline, subtle coloring (not to mention exquisite pedalling), dynamic variety, tonal variety...etc.