imx series have already been used developing embedded linux. There are plenty of people familiar with imx hardware and and embedded linux and develop some hardware on the top of imx. If Librem5 has some hardware development pinout like I2C, SPI, GPIO, UART, isn’t it so cool?
Motorola carried out this property with moto z play. It provides a hardware user interface and one creates own hardware working with his phone. You can see the details from https://developer.motorola.com/tools-kits
I guess if there will be such a hardware support, it draws embedded linux developer more than now. Many people creates custom hardware like raspberry pi hats then they transform Librem5 into more than phone.