Completely agree about having the currently running line highlighted in the program window.
If I use single-block mode in (v3.29.1a) I notice a highlighted line does track its way down the program, but it is definitely not tracking properly.
This actually through me off at first because my tool changes were happening several lines further down the program from the actual Txx M6 line.
I've also noticed the CTRL-O toggle for optional stop seems to be sticky with the keyboard, that should be looked into.