400mbps All-I is great, but I would prefer an option for 400mbps IPB. Not just because it could potentially net better results, but also because it would open the door for 4K 60p in VFR mode.
I think it all depends on the camera having enough processing power to make use of the higher data-rate, so I would not expect any details to be set in stone until much closer to the actual release date.


