How big do you want it?
As small as possible.
Do you want other ports to be able to charge other things with it? And if so, what kind of ports?
Other ports yes, but not for charging per se: HDMI/MHL Since is the only port missing on PF and since the charger usually always go with me anyways... that will erase the need to carry around a USB-C to HDMI dongle.
Do you want data transfer through the charger?
YEP, see previous answer.
Should it plug directly into the wall or should there be cable?
Cable, with standard Power supply on one side USB-C on the other. That way finding replacement cables should be easy.
Should the wall plug be replaceable by the user?
If there is no wall cable, yes. See previous answer.
Should it only include one localised wall plug, or should you get them all included?
Only one. If people need to travel they usually get an adaptor on location.
Should Eve put their logo on the charger?
Hell yeah, and as Hi contrast as posible, no leds is waste.
Do you have any stand-out examples of chargers that either did it right or did it wrong?
None comes into mind.