@tenaja I've not seen those before, they look like a very interesting concept.
I think for this usage they will take up too much space and cost too much, but I do wonder if the concept could be used - Maybe add-on boards that can adapt banks of outputs to meet various requirements. For example you might want relay outputs, or open collector outputs, 5V outputs, 24V outputs.
I'm trying to balance this with the space usage because I think for the people who are likely to use it (For "desktop" to medium CNC machines essentially), they are likely to have limited space in their control enclosures. For myself, I need to fit everything in a steel enclosure which will slide out beneath an Ikea Lack table which gives me about 500x400x200mm - VFD and all. I think I can get the size down to about 100x50mm or less.
I've also been considering the selection of some of the connectors. I've chosen a right angled RJ45 & RJ11 connector with the release tab on the top, a "flip up" SD card holder which could be mounted away from the edge of the board and a "vertical" micro USB connector which again can be mounted away from the edge of the board. I might even do away with the reset button / external reset input as I don't think it's really required for this application. On the flip side, I'm going to add a lot of status LEDs for every input and output for example.
I typically use EasyEDA as I really like their library integration and I'd probably use JLCPCB's assembly service, but sadly some of the components (The processor for example) do not seem to have footprints right now. I've tried all of the PCB / Schematic software packages and I'm yet to find one I'm really happy with.