There were two things I liked about the Panda I and II, but they are probably things that won’t come back: the carrier boards and the eBlocks.
The Panda I had the Tinkerer base board - the Panda II had the [other thing that I don’t remember the name of] base board. I didn’t use those on all projects, but it was nice to have one system with an expansion/breakout laying around for prototyping. I am not saying that they need to come back - just saying I liked them.
I also liked eBlocks. The expansion shield with simple 3 or 4 wire interfaces was simple and Fezzy. Of course, that’s what I like about gadgeteer too. But the eBlock cable made it really easy to wire up just about anything - even if you needed multiple cables to connect a single component (like a joystick). Again, not saying that they need to come back - I just liked them.
In those days I ran about 100 engineers through beginner .netmf classes and each one took away a kit that they used for all kinds of projects.
I like Gadgeteer. I like the plug and play, drag and drop, good drivers for everything. Panda was made in a way that made you think you could connect anything, not just things from the catalog. Yes, you can do that in many ways with Gadgeteer boards - there is no limitation - but the Pandas encouraged it.