I would love to see some "pro" features hit the Pro or Pro Max. Something I've wanted for a while is the ability to have more than 2 active eSIMs; I think a dual modem would be really cool, maybe with some features targeting users in poor cell coverage/ spotty service areas.

Or feature Thunderbolt rather than normie USB-C so you can record 4/8K ProRes to an SSD, and power a multi monitor setup with your iPhone Pro. macOS would be sick. Or (waterproof) exposed PCIE lanes so 3rd parties can integrate an ecosystem of backpacks like how Pi Hats work.