I might be misreading your post, but there's nothing stopping you from using a gcc+make+$EDITOR workflow with the Kinetis or MSP430 chips either. I've done both

I might be misreading your post, but there's nothing stopping you from using a gcc+make+$EDITOR workflow with the Kinetis or MSP430 chips either. I've done both, it's not even painful. (Admittedly I haven't worked with MSP430s in about a decade, maybe the situation has changed, but it seems unlikely.)