How do you think I arrived at the 60K figure for size? 56K is the absolute best case for the most popular chip choice. That’s using the small, B&W LCD, not the larger color touch one (>12K more flash used), that doesn’t include the new voice-based audio output (a very popular feature), the current rewrite of the UI for new transmitters with a different set of buttons. or any other ongoing work.
There is a guy who’s working on porting micropython to the 128K STM32F103 that we use in our low end devices, and he claims to have it down to 40K, which is small enough to be interesting. But he also says you have to use compiled-into-flash Python code, not scripts from the file system, because he took out the REPL. Taking out the REPL shouldn’t require compiled-into-flash, and I’m fine without a REPL, but can’t live with compiled-into-flash. I’ve asked him for clarification, but haven’t gotten an answer yet.
But Rust being easier isn’t the relevant question - it’s whether or not it’s harder for non-programmers than Python. The borrower and associated stuff are a PITA - for programmers. People with no programming experience won’t be having to unlearn things, so I don’t think it’ll be much harder than dealing with a garbage collector, and certainly easier than what C/C++ provides. A lot of people are learning embedded programming using C/C++ to control Arduino hardware (which frankly surprised me), so I’d expect them to be fine with Rust.
And a lot of users won’t be doing programming per se; they’ll be editing scripts to replace the name of a switch that was on the original authors transmitter with one that’s on theirs, or inverting the sense of a switch because that’s their preference, or changing a value because the used a 4x voltage divider instead of the 5.5x divider the author used, or something equally trivial.
Well, they need specific tools to install the software - and that’s the major source of user problems. Once it’s installed, it presents it’s sd flash as a USB drive, and that’s how it communicate with desktop systems. There’s an LCD screen - possibly with touch - and a collection of buttons, switches & analog input devices for tweaking settings and the like, but those aren’t really available for editing scripts. Imagine programming with an XBox controller.
So the primary tool for installing shared model files is the desktop, and the primary tool for editing them on the desktop Notepad++. And that causes sufficient pain that we’ve had people write desktop tools for managing/installing or editing those files - and almost no one bothers installing those tools.