wiglytuff for ubers lololol
more seriously, I think some things with fairy typing would become decent to super good picks for ubers. For example, I could see accelgor being a decent offensive spiker with bug STAB, dragon immunity, and dat speed for checking darkrai and co.
Jynx I think would also be much more viable, setting up on most choiced kyogre AND dragons. Lovely kiss + NP + Ice STAB is pretty great, too.
Both blobs would become much more viable, as well, since rayquaza can no longer outrage them and neither can kyurem-b. Also not being worn down by repeated draco meteors would be nice.
Cryogonal, being able to break most spinblockers, would be a decent spinner and semi-reliable special sponge. Being able to wall kyurem-w's STABs would be a bonus woth mentioning.
Manaphy, all the grass types on the list, and froslass could also be good wielders of this typing.
I think with fairy we can expect a jump in popularity of offense for a couple reasons, despite the dragon immunity. Stall would be way worse since now dragon tail immunities would be pretty annoying (though substitute ho-oh is already annoying for d-tailers). This tremendously nerfs both giratinas, two of the three common spinblockers, which means ghostceus is the only one not hampered by fairies. With this, I think spinners will increase, so things like toxic forretress, toxic cryogonal, tentacrual and kabutops and excadrill will be more difficult than ever for stall to handle (since ghostceus is hardly as good vs. kabutops and excadrill as the giratinas are). But none of this might happen if xy introduces some amazing new defensive threats that stall can take advantage of.
On a different note, I think dialga will increase in usage since it can use flash cannon or iron head to break fairies easily.
EDIT: Also looking forward to using azelf and cresselia (finally has a niche over lugia YES)
EDIT 2: Also alomomola (lol) might be sorta cool as a rayquaza check with dragon immunity+ fire resist, and a decent ho-oh check if sun isnt up though with ho-oh involved it probably will be).
Also, xatu wont have that much trouble with dialga anymore, so take THAT espeon!