I'll throw my hat in. I think the problem with the injury system is the fact that it exists for the sole purpose of forcing you to rest. Ideally, injuries should be balanced not to force you to rest; resting should be something you do to keep your characters from getting to worn out. That sounds contradictory, but I guess what I'm saying is that as is, it's too straight forward.
For one, it's unreasonable for injuries to be healed from resting and eating food. I'm not usually one to argue for realism in a game, but I think it's pertinent in this case. It's too easy to do, and virtually negates the decision of "do I rest, or do I press on?" Of course, you rest, at different times depending on how much of a health penalty you can handle. I think that instead, if you get an injury, it should slow you down until you get it treated. Food doesn't treat an injury, it gives you energy (i.e., endurance). Bandages, stitches, and giving the injured body part a rest, that's how you treat an injury.
For the sake of both verisimilitude and balance, what if you can offset the endurance decrease with food, but the actual injury type itself (bruised ribs, concussions, etc.) stays until you rest it off with bandages or some such? Of course, for that to work, you'd have to make injuries give a severe enough debuff that after two or three, you're strongly encouraged to rest. I also think it would make sense to keep the stacking of four injuries = death system they have currently.
TL;DR, I think they should make the process of removing the health decrease different from the process of removing an injury like a concussion, and make the latter have a more severe effect on combat. This way, it's less of an obligation and more of a decision.
I can tell you right now, most people would decide to rest than to press on, even taking skill level into account; some people just don't like working with characters that aren't at 100%. Anyone who doesn't mind is already much less likely to rest, even with the system as is, as can be seen in this very thread.