The DPP council has agreed to knock the Pokemon currently in OU that haven't been used or considered usable in the tier for a decade down to BL. These Pokemon are:
Dusknoir, Electivire, Umbreon, Smeargle, Ninjask
Similarly, some BL Pokemon that are considered good and are seen in standard play are being brought up to OU to provide a fuller idea of the tier.
These Pokemon are:
Abomasnow, Cresselia, Crobat, Heracross, Raikou
Marty please implement these changes, thank you
For anyone wondering why Clefable and Nidoqueen aren't OU, it is because they reside in DPP's lower tiers that are still played in tournaments.
If you would like to suggest any currently OU Pokemon for BL and vice versa and are prepared to back this up with reasoning, you may do so here.