There is a rule in the Spanish league to win the Award of better Goalkeeper, and is that a GK have to play at least 28 of the 38 matches that the league have.
This rule have to be here too, to do rankings like this... I too have as first ranked my player Arjen Robben, with a 8.0 of valoration, that played only 4 matches, and all as a sustitute in the 2nd half... and really I prefeer to see the most active players in the ranking...
I did not think in do a ranking or a category of award for this type of valorations for this reason...
or well... thinking in the situation... we can see who is the better if we put one picture like your, of the Top ranked of valoration, + the personal statics of the player to see how many matches did he played this season... is the only form to show really that is a % of 20 or 26 matches.... I will think in it...