You don't have to break out EVERY pin.
4 servo plugs, 4 ADC plugs (mix 5 and 3V), and a 4-6 long 3.3V rail and a 4-6 long 5V rail is what I would recommend.
To be fair, having only 4 and mixing voltages would be a bit strange and potentially problematic. I think just having rails isn't a bad idea, and just leave ADC at 3.3 for consistency with the old boards.
You don't have to break out EVERY pin. 4 servo plugs, 4 ADC plugs (mix 5 and 3V), and a 4-6 long 3.3V rail and a 4-6 long 5V rail is what I would recommend.