To my knowledge, all of the GameCube versions of *Metroid Prime* and *Metroid Prime 2: [Dark] Echoes* only support 4:3, not 16:9 .
Currently, Dolphin's widescreen heuristic will fail to detect this and will erratically switch between 4:3 and 16:9 when Aspect Ratio is set to Auto.
These changes prevent the erratic aspect ratio switching by manually declaring that the game is solely 4:3.
These games greatly benefit from CPU Culling, and there isn't much reason
not to just blanket enable it for all users. There is no case where you'd
want it disabled.