I'm not playing the devil's advocate. But let's stop this because it's not the reason the topic was made.
I'm not going to say the passive should be removed. Crusader has a ton of resources to stay alive forever and pretty much needs a spot for counterplay (his lack of damage isn't the point here, since he can provide an endlessly support to his teammates with heals, shields and % damage reduction).
Thing is, the -healing debuff is too long to maintain with only the skill that was meant to (Aura's Shield), so my suggestion is: Decreasing the -40%healing debuff's duration to 4.5s just like Aura's shield.
Why? Because if you don't want yourself to be burst down, you'll need to give up one of your key skills on surviving. That makes sense.
Right now, it's 10 seconds, you need to use 2 or 3 key skills to maintain yourself "tanky" while the passive is up, that's not a viable mechanic (as i said before, you better let your friend die so you can save your resources to stay alive yourself).