Gamepad 2.0 not recognized as a standard/generic gamepad + other Gamepad problems
The Gamepad 2.0 is not recognized as a standard/generic gamepad, so even games that are natively compatible with gamepads like Fortnite does not work instantly like with all other gamepads by just connecting them with bluetooth, you have to map all the buttons each time with each game ! Another problem with not being recognized as a normal gamepad is that we can't connect 2 gamepads and play 2 (or more) players games (on emulators or android split screen games like Beach Buggy Racing or Riptide GP Renegade). I don't know if it is possible to software update the Gamepad 2.0 but this is the most important to do.
Secondly, it should have 2 joysticks rather than 1 joystick and 1 touchpad, Sony Xperia Play and Steam Controller have already failed with touchpad controllers, people wants 2 joysticks like on Playstation, Xbox and Nintendo consoles, so making a new right gamepad H66RS with a joystick would be nice. Also the Gamepad 2.0 lacks L3/R3, Start and Select buttons, this would mean making a Gamepad 3.0 but it would be great. And additionally, some games like Street Fighter 4 can be controlled in game but not in menus, so a button to switch to mouse mode like on many cheap Android gamepads (ipega for example) would be perfect.
Finally, we can't play with the Gamepad 2.0 attached and charge the phone (or plug headphones) at the same time, this could be fixed by placing the USB-C port of the Black Shark on the left or the right side rather than on the bottom of the phone so you should consider it for the Black Shark 3. But keep the wireless two-sided design of the Gamepad 2.0, it's the best for portability and strong attachment to the phone (better than all others).