It would be interesting to try a new model of joystick ergonomics. Maybe a flattened cube shape with a single switch on each vertical facet (up, down, left, right). The top might have 2 fire buttons.
OR
Start with the same box and use industrial spring loaded toggles - one for up/down the other for left/right. The switches could be installed, again on different faces, with the plane of toggling naturally oriented to the direction they serve. This could be a very intuitive and responsive controller. Might look kind of like a steam-punk design.
Fun to think about.