Because of the ladders, it would need some extra logic to replicate what Elite originally did for amiga Ghosts'N'Goblins. Personally I found the controls super frustrating with 1 button.
For me, it's exactly the opposite. I play all games of this type on the C64 or Amiga with a joystick. This two-button control is quite frustrating. But if it's not possible or too difficult to implement, then I'll just skip the Ghost N Goblins AGA version. I'll have a short report on Ghost N Goblins AGA in my Retro News Flash this coming Saturday.