Summing up projects I've done in few recent years I've come up with list of things I'd like to have on MY development board.
- It should be breadboard friendly, this is where it spent lot of time, and it should be comfortable there
- It should deliver power to breadboard, why have two devices, where one will do
- I want to have more leds, any reason not to have one per pin?
- OLED screen is nice to have
And few extras and nice-to-haves
- Since it is development board, it should have some pin cheat sheets
- When development is done, it could serve as actual device, so usb-serial adapter is optional to save costs in the 'production'-kind of run
- It is size compatible with Paspberry Pi cases, thus nice looking device in the end
- From my personal experience working on audio solutions, SOIC-8 IC is the most popular add-in, why not to have a space for it on the board?
This is work in progress and I'm preparing first prototype at the moment.