Fill has a classification of less diversity than two roles do???

title explains it concisely. to put it into practice do this. get three people in a ranked lobby. two of the 3 people will secure their roles by choosing the opposite of each others roles (i.e. one selects jg and supp, the other selects supp and jg) The third player must select two other roles, but if the third player pick FILL which is really the most versatile role, the que cant start and the person is forced to reduce their decision to two exact roles, making que time unnecessarily longer and forcing a decision for someone who doesn't want or care to make it.