my opinion it comes down to nijinsky  or albano
i eliminate legendary based on poor finish to the year and he was 4th in na cup and did not race in breeders crown
i eliminate mirage hanover based on missing na cup final and seventh in m pace
also both of above won $1.1 m , significantly less than both nijinsky and albano
nijinsky was first in na cup, second in m pace, second in breeders crown
       missed top three only twice, jug elim and progress elim when parked mile
       won $1.66m
albano was third in na cup, ninth in m pace and third in breeders crown
      also only missed top three twice
      won $1.5 m 
albano finished year very strong and looked dominant
my only knock against nijinsky as consistent as he was is that he never really looked like the dominant horse for a period of time 
close call but i give slight edge to albano