I might have misunderstood model E. For me, it shows 3 Grove connectors.
Back to my initial post, I see two use cases.
1. Development expansion board
The aim is to facilitate development with the SWD plug for debugging, all pins exposed and 3 or 4 Grove connectors for external devices.
2. Expansion board
The goal is to provide a set of must-have peripherals like extra Flash, microSD-card slot, battery for RTC, screen, battery manager, RGB LED, all pins exposed and obviously plenty of Grove connectors.
This second use case could be expanded with a set of climate sensors (temperature, humidity, pressure, air quality, light, UV, sound, …) through one single I²C bus.
- To answer your question,
I would prefer a square board rather than an hexagonal one. Another criteria is the final price, which needs to be consistent with the affordable Xiao.