“Could do with an extra GP0, GP1 (and potentially GND and +3.3V) to allow connection of Debug Probe as otherwise a slot is wasted. [The +3.3v would allow power from a pico debug and only one USB]”
“In addition, it would be helpful to have an addon board providing access to the default ports via JST 2mm to RP2040 I2C0, I2C1, UART0 RX/TX, UART1 RX/TX and SPI0, SPI1 using the pins around GP12-15 and GP16 - 19.”
“Just what's needed when working with a Pi Pico and an expansion pack -- particularly a display pack -- as they normally fit back-to-back which makes it difficult to get to the BOOTSEL button and see the display at the same time (without using a mirror or twisting the space-time continuum). It would be even better if it had RESET button, and better still if it had an ON/OFF switch (to power-cycle and reset the pack).”