With the A9ii Sony appear to have listened to what have been stated as deficiencies in the original A9, and fixed a number of one which might have been holding back sales.
It's not a revolutionary upgrade, but certainly helps remove some negatives that might have people choosing alternatives.
Dual UHS-ii slots - Keeping Raymond happy

Mechanical Shutter now does 10 fps, and rated at 500,000 +
Improved weather sealing
Improved connectivity
Voice memo
All are making it a more 'Pro' camera - better able to compete with the 'solid' traditional DSLR's - which is where Sony want this camera to be, lined up alongside the offerings from Canon and Nikon at major sporting events.
And for the rest of us - potentially a drop in A9 prices, and more s/h A9's on the market