I don't recall how ag_UF did this/what it looked like, but is it similar to combat text or bar fading?
Well it was kind of like an SCT for for the unitframes. Actually, yes it was SCT for your unitframes, as it showed for everyone, and really helped out with healing. It's nice to see when your MT gets a string of dodges, and when he just got a crushing or the special ability landed on him.
Basically if I'm looking at it and see an average hit of 5k it's easier to use the proper heal, and when that number jumps to 10k it's much easier to know it's one of those 'oh shit' moments and rank up for a cast or two to top him off.
Of course this isn't necessary on all frames, however if it was say possible to enable it on your target frame, that would be great. If I remember correctly it popped above the portrait for AGUF.