As a practical matter, for developing, a rooted Android device is going to be better for developing as everything's standard and easy to work with.
As for GPL compliance, that really only means anything for the kernel. For the rest of the software, they can easily be closed sourced and not provided. Not that they necessarily wouldn't be, but I'd still rather have an Android device with an unlocked bootloader and no kernel sources.
As for GPL compliance, that really only means anything for the kernel. For the rest of the software, they can easily be closed sourced and not provided. Not that they necessarily wouldn't be, but I'd still rather have an Android device with an unlocked bootloader and no kernel sources.