OpenGL is good for a lot of what DirectX acheives. There is an Amiga version of SDL which can make up for another slice as it does sound as well as well as GFX. I am not sure you would need too much more than that in the GFX department. Both are multiplatform and would be good for an amiga company that wants to make amiga games and sell them for other platforms as well.
Think about that though. If they made a game for the amiga that was easily ported to Mac, Linux and PC's the sales could supplement the money made from the amiga version hence making more games comercialy viable.
Also the porting of Open Source Games to Amiga would mean that we could have games much sooner rather than waiting for some one to develop them from scratch. Many Open Source games use API's such as OpenGL, OpenAL and SDL because they are free.
