Headstocks are underappreciated.
They provide a platform to hold the tuning keys, and as such determine:
1. The ergonomics of the tuning process — player's reach and visual connection: comfortable or awkward? The first photo below is a 5-string Fender Jazz bass, viewed from the player's position. Easy to see and reach the top four tuners. The bottom tuner is hidden. Annoying. Plus you have to remember which direction to turn the bottom tuner.
2. Tuning stability of the instrument — precise tuners are a pleasure to use, and stable. Strings that pull in straight line across the nut from bridge to tuner intonate better and are more stable. Designs that force strings to splay place bi-directional force on the string slots, creating potential sticking points as the strings change direction. Bad.
3. Tone of the instrument — rubbery or solid? Along with neck flex, headstock flex affects tone.
4. Strength of the instrument — neck to headstock joints are vulnerable. More on this topic soon.
5. Balance of the instrument — heavy headstocks pull the neck to the floor, forcing you to support the neck as you play...and headless instruments often bounce around as you play because the counterweight of the headstock is missing: neither situation is desirable. More on this topic soon.
6. Visual signature — The shape of the headstock is dictated by the above (surprisingly constrictive) mechanical parameters PLUS a little mojo: builders often use headstock shape as a visual signature. And aggressively protect their shape. Copy a Fender, then stare at the second hand on your watch as you wait for their lawyers to contact you. See the composite photo below to guess where Leo Fender got his design inspiration (hint: instrument on right is a cello).
Orchid's minimalist headstock (paper template below) is a blend of the elements I like best. You'll notice it deviates from the original scale drawing. I reserve the right to change my mind.