I had some fun with this device - https://shop.m5stack.com/collections/m5-hobby/products/rover... - the general platform is geared more towards IoT, sensors and what you can do with software, but perhaps that's even a more relevant direction than just motion.
I was looking for a Christmas present robot kit for my 8 year old and still on the fence between mindstorms or the makeblock robots. (The Codey Rockey in particular, but the mbot looks really nice too)
I have colleagues that organize coserdojo sessions for young kids fully centered on the makeblock robots. You can program them in scratch to get started, but a push of the button gives you the equivalent Python code once the kids graduate from scratch.
I am surprised to see Lego cancel mindstorms, but it does make the decision easier…
Generally arduino, or raspberry pi. Learning to light up an LED and move a servo motor, plus read some kind of sensor are great ways to start to see how code can interact with the real world.
There is a different feeling when programming things in the physical world, especially if you only programmed digital creatures before :) Give it a try if you haven't, Lego is a great non-intimidating way of getting into it, otherwise Arduino is pretty simple for programmers to grok as well.
