1. "Hands on controls" switches, controls.
2. Lighting, inside and out. Provisions to minimise reflection and glare. Pilot serviceable bulbs would be nice, as well.
3. A dry, handy place for RFM, charts, etc.
4. "Boudreaux"-proof doors, windows, seat belts.
5. If I never saw another greased bearing in my life, I'd be happier.