With all the discussion about sane key defaults, I am wondering why there isn't a input settings screen hidden somewhere.

I want to grad free balls with left-click, grab used balls with right-click, speed up the game with right-click after meeting the criteria & whistle for my goos with double click and middle-click. And I want to be able to use shift, ctrl, alt, whatever to choose which type of goo my clicks affect.

Others don't want that, they want a different layout.

Why not cater to _all_ by offering to change stuff according to your personal preferences?

Yes, it takes away some of the 'just play' factor, but in this case it is a good thing, imo.