Did you use Memory Link TC? If you did, you can fight Cheren with his BW1 team on Route 5. Also the Nimbasa Domes now have strong ass trainers, the Royal Unova ship in Castelia City also has strong trainers
you can now also visit the BW1 areas that were locked off.
And don't forget about that Zoroak on Victory Road.., also go visit Alder in his house.
I'm waiting for nightime so I can evolve a certain Pokemon before tackling post game