Are there really significant use-cases which require both a higher performance processor and GPIO pins? I imagine at this point there is value in splitting the product line to tailor towards "mini Arm server", and "IoT/robotics" users separately.
You need gpio pins for random kiosks (web access, photo printing/scanning, etc. to control the leds, lights, etc., even coin slots), retro arcades (to get input from joysticks, buttons, etc.), robotics (camera for video, a lot of cpu for processing, gpio pins to control the movement), advanced sensor boards (where the processing is done on the device), smart home stuff, etc.
"Back in my time", we used to use parallel ports for that... 8 very limited gpios were enough to drive a few leds or read some data from an external device.
Think a terminal in a Museum with lights, think a local hotspots with sensor and connected (normal tablets), think a ECG machine, ... . Use Cases there are enough, whether other criteria (like quality/reliability) are sufficent, is another story).