I would like to see a DSL such as RAD, except that RAD doesn’t actually work, but if it did, it’d be excellent. The Ruby syntax is friendly and approachable.
Ideally I would like to see a modern Forth on the Arduino, but apparently that’s not possible because it has a Harvard architecture.
Alternatively, I think a DSL built in Lua (which is simple and understandable, but not quite as friendly and approachable as ruby) would be excellent. I don’t mean (of course) running Lua on the chip, I mean using a framework on the Mac that uses Lua syntax to propel a compilation down to atmega binary which ends up on the chip.