Pretty much what the title is saying. I'm from back before the UI update and I highly prefer the old ally HP over the new one. Not because I prefer the look of it. It had pretty important information regarding the integrity of the allies' HP. You could see whether they had less HP blocks or more. This way you could estimate the durability of said person and take it in mind.
https://www.youtube.com/watch?v=bxARLatEJ58 An old example of the HP in the old hud. Thx to Vokster for the video.
Here you can see the amount of bars of allies. Like I said, this was also adaptive so it could show 5 bars for little integrity and at times 20 bars which showed you were pretty durable.
Please bring this feature back OOO. It helped a lot, not only in PvE but also in PvP.
If your teammates had heart trinkets, chances are their health exceeds 20 pips. As a result, you can't tell if they're missing HP or not with the old system. They could have 35 bars of health, be missing 14, and anyone at a quick glance would see no difference on the HUD. The bar showing how much health they have relative to their total health is more useful than showing only 20 pips, considering stacking HP bonus is pretty much, well, the meta.
Not that knowing exactly how much HP they have even matters anymore; your teammate is responsible for their own health, as there are 4x the pill pickups as trade off for not being able to share them.
Furthermore, there is nothing stopping you from taking 5 seconds to inspect someone to see their trinkets and gear before you jump onto that first party button. Now, a change that would actually be nice? Make the character "portraits" smaller, especially the one of your own Knight. They're too bulky and not really necessary.