Now that the lower tiers of old generations have been unlocked, it seems that there are going to be quite a few changes to the tiers (most notably, Conkeldurr is probably getting suspected from ORAS UU and the BW sleep and Shadow Tag bans being extended to the lower tiers.) However, is there a possibility that some of the "redundant" Pokemon from upper tiers are going to drop to BLs? For example, Dugtrio is stuck in BW and ORAS OU without Arena Trap, as is Abomasnow in BW UU without Snow Warning.
(I'm referring to specifically those that were in the tier with good reason originally then had their viability taken away completely by a ban, rather than Pokemon that were placed in the wrong tier by bad players and aren't used anymore like Donphan in BW OU.)