Not sure how you are seeing the QB actively read a guy.
But I do have an idea about that.
I would love, in the Replay, for the Target the QB is currently reading to be hi-lighted in some way, and we could literally see his progression.
If he's running for his life not looking down field, no one would be Targeted, but as soon as he's clear enough to look downfield it would 'spot' the guy for us, and continue as he went from Target to Target.
****, I'd like an Assignment Key, really. Pre-Snap (where we can also Pause) it would show who each guy is designated to block (in Run Blocking) and would shoe the Defensive Assignments.