It's already visible with the red -> black bruising; just you need to take the time to learn which colours equate to roughly how much force is being applied. Also not using shitty force colours like Void helps unless you're only playing in low DM mods. For obvious reasons Vamp etc kinda sucks for it too.

They go completely black at around 1k force, sorta dark-reddy-dogshit-bown at 500ish, and hit a Vampire shade at approx 250.
Under 250 it's a more or less linear scale of slightly red -> red red, above that it can get difficult due to LCDs being pretty bad at colour reproduction.

Once you get used to the colours it's pretty easy to get a fairly accurate idea, so it's not like a script is going to make it easier. If anything it's just yet another distraction that'll take your eyes from where they should be.