TL;DR
Health bars can be hard to see, so highlighting / making them more prominent while holding a repair pack would be a great addition.What ?
There's a health bar "visible" here, even with the character in the way...but you can imagine how easily this would hide with more clutter around!Maybe a thin red rectangle around the health bar itself? Lots of options.
Why ?
Just as the highlights for rail signals, offshore pumps, pumpjacks, etc. have improved interactivity with those specific things in hand, so too would additional UI behavior for repair packs.(Similar thread for underground belts / pipes, not yet implemented: viewtopic.php?f=6&t=40046)