Looking on last year's qualifying comparison, the difference between the cars at the old track was small. I also agree with the wider community that the new track changes take away the premium on rear traction thus the advantage will swing to Mercedes.
Examining last year's qualifying:
The RedBull seems to have better low speed traction on corner exit as you see in old turns 5, 6 , 7. Then on old turn 8, the Mercedes seems like it catapults from the corner. This was not because it has gained a strong rear end all of a sudden, it was only because of the off-camber corner that helped to load up the Mercedes rear outer tyre. The story of strong rear end and traction repeats for the RedBull out of turn 17 where it pulls ahead once more. The rest of the lap is pretty even stevens. One thing I noticed was the RedBull seem to lose tyre grip later in the lap.