I had to think about it for a few days, but I think I figured out what's been bugging me about the new injury system. The reason I don't like the new injury system:
Not all damage counts. If you still have 1 point at the end of the fight, nothing bad happens. It is very binary - you get injured or you don't. It's punishing, but that punishment is arbitrary.
With the old health system, every time you got hurt, you felt it in that slowly decreasing health bar. Getting knocked out had a separate consequence to taking damage. Your character's had too much health - that's what made the system so confusing... you get hurt, you get back up, you get hurt, you get back up, you get hurt, you get backup, over and over until suddenly you can't get back up anymore. It took a long time to reach that point of meaningful feedback. Everything had a consequence, but the consequence was too small.