On the sonoff boards, you have pins that tech savvy folks could benefit and use. Some of them may not be comfortable on soldering, but comfortable to connect wires etc. Can you provide a builtin female or male connections for - 3.3V, 5V, GND, TX and RX pins.
This will be a huge win for lot of DIYers.
And GPIO 14 and any other unused GPIO pins made available for ease of use. like raspberry pi has 40 ready to use.