Well they could've done something like allowing gym rematches in BW1 and then branching out to something even better in BW2, like previous gym leaders/E4/champions.
And, if all the unconfirmed info on Serebii right now is true, that seems to be happening anyway.
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First is mnk'boy'907, who looks fab with her gray skin and grandma poncho/shawl thing~
http://img.imgcake.com/nio/boypngbu.png - Nio