STRAIGHT is interesting; it’s the only other temporally-addressed architecture that I know of, and I thank you for bringing it to my attention.
The addressing (STRAIGHT vs Mill) is different: STRAIGHT refers to the generating instruction in time order, whereas Mill refers to the dropped result. In the hardware STRAIGHT uses a scoreboard approach to block for uncompleted instructions, while Mill uses full static scheduling. Some benefits are shared: no renaming, no encoded result registers. Some are peculiar to one or the other: Mill needs no reorder buffer, while straight need not track instruction retire time in the compiler.
I wish them luck.