Even he would have to put Tatum first! (Actually, Tatum is not a top favorite of mine, although I do appreciate him, but every last pianist seems to revere him, so I bow to their wisdom...) And don't you think Previn would be embarrassed, too?
Not even Hines, Basie, Ellington, Teddy Wilson, or Jelly Roll Morton made this top ten. The mind boggles. But at least they made the list.
I wouldn't call it a conservative list -- I'd call it clueless.