I'm not sure which of the info I have are public, and which are confidential, so I can't elaborate. But you can compare the (limited) info published on Broadcom's website. For instance the BCM4912 adds support for two 10 Gbps ports, and DDR4 support (which means an upgraded memory controller at the very least).
Sorry for the ignorance , will the AX86UPRO introduce VLAN support?