Thanks for the additional comments.
Regarding Ethernet support and a web interface, the Duet electronics and firmware provides an excellent web interface at the same time as running the printer, all on a 84MHz Cortex M3 processor with 96K RAM. The benefit is huge IMO. Once you have used the web interface, you never want to go back to Pronterface. You definitely do not need to add a RPi or similar to get this functionality. Having the web interface built in means that it can provide information that is not available via gcodes, and continue to provide real time information when the printer is executing commands that take a long time to complete. I can see that having a single web interface served by an RPi or similar may be a good solution for controlling several printers, but most people have only one printer.
I agree that many users would find wifi more useful than an Ethernet socket. However, it is a simple matter to connect an inexpensive wifi to Ethernet bridge to the Ethernet port. The worst part is having to provide power for the bridge. Maybe a USB-A socket should be included on the board for this purpose. A wifi piggyback board could be another option.
Regarding the development environment, Arduino is great for novices, but both the IDE and the core libraries are in my experience woefully inadequate for serious firmware projects such as 3D printer firmware. As long as most users never need to build the firmware, the development environment required is not important as long as it is freely available. Eclipse is the obvious choice for open source firmware.
Regarding a 6th stepper driver socket, the constraint is board space. Another hot end mosfet would also be needed, requiring yet more space. A thermistor to measure enclosure temperature could be connected to the expansion connector.
Regarding Ethernet support and a web interface, the Duet electronics and firmware provides an excellent web interface at the same time as running the printer, all on a 84MHz Cortex M3 processor with 96K RAM. The benefit is huge IMO. Once you have used the web interface, you never want to go back to Pronterface. You definitely do not need to add a RPi or similar to get this functionality. Having the web interface built in means that it can provide information that is not available via gcodes, and continue to provide real time information when the printer is executing commands that take a long time to complete. I can see that having a single web interface served by an RPi or similar may be a good solution for controlling several printers, but most people have only one printer.
I agree that many users would find wifi more useful than an Ethernet socket. However, it is a simple matter to connect an inexpensive wifi to Ethernet bridge to the Ethernet port. The worst part is having to provide power for the bridge. Maybe a USB-A socket should be included on the board for this purpose. A wifi piggyback board could be another option.
Regarding the development environment, Arduino is great for novices, but both the IDE and the core libraries are in my experience woefully inadequate for serious firmware projects such as 3D printer firmware. As long as most users never need to build the firmware, the development environment required is not important as long as it is freely available. Eclipse is the obvious choice for open source firmware.
Regarding a 6th stepper driver socket, the constraint is board space. Another hot end mosfet would also be needed, requiring yet more space. A thermistor to measure enclosure temperature could be connected to the expansion connector.