> Isn't WhatsApp still purportedly end-to-end encrypted? What data is "on the table" when it comes to sharing - just contact lists and phone numbers?

It is, and same is claimed in their privacy policy and ToS. According to the original article it will include, what is already being collected:

    User phone numbers
    Other people’s phone numbers stored in address books
    Profile names
    Profile pictures and
    Status message including when a user was last online
    Diagnostic data collected from app logs

Along with possibly:

    Purchases
    Financial information
    Location
    Contacts
    User content
    Identifiers
    Usage data and
    Diagnostics

A little more than contact lists and phone numbers.