Yes, you are right, that specific linked gadget kills portability to a large degree. However, there speaks nothing against making a gamepad more specific to thi

Yes, you are right, that specific linked gadget kills portability to a large degree. However, there speaks nothing against making a gamepad more specific to this use-case so you have better portability. Of course this approach will not be as good as dedicated controllers on the device itself, but I think it would be enough.