Before I get into specifically quoting other posts, I have a proposition that expands on what several others have said:

What if all Warrior self-healing was converted to shield-generation? Instead of regenerating actual HP, you build up buffers of temporary HP to soak the damage that PLDs mitigate. Healer's would still see your HP bar's level as green and your temp HP as lets say blue, so they know when you need healing and when they can leave you alone for a moment. This also allows WARs to be preemptive in their ability use instead of reactive; you see a big hit coming, pop Inner Beast and you'll negate a large portion of it.