As someone pointed out sooner, warlords could heal unconscious character because they could heal and direct/command an army of deaf, blind, one-legged lepers.
He could command them to get up. And that assumed they weren't deaf/blind for the othe 99% of the time they are under his direct command. The Warlord has a LIMITED number of ways to effect dying characters. Also, unconcious may mean unaware of your surroundings for the most but no matter how deeply unconcious one might be, there is little to know that nothing is getting through. It may be something that breaks through the fog and snaps them back likea bucket of cold water [metaphorically]. Something that pulls them back in.
It makes no sense to me that a warlord could affect anyone deaf. I'm hoping in some other life, the Divine keyword of all cleric powers versus the Martial keyword of all warlord powers will mean something thats not just a technicality.
Deaf and dying are different. You ASSUME that being unconcious makes one effectively deaf [I'll give you blind ... your eyes are probably closed and thus effectively]. There is no mechanical implication. It may be that you are not CONCIOUSLY able to hear and understand what is going on, but your subconcious is still receiving stimuli, and your warlord is able to inspire your struggle to survive. He tells you not to die, so you don't.
Ultimately, this is ONE power, which is the "generic leader power". How does quarry work by the way? Sneak attack makes sense, it's strategically hit spots on the anatomy that do more damage. Curse damage is magic, thus needs no explanation. Quarry is martial and is basically "favored enemy this guy, until I change my mind".
It's generic striker ability.
Most of the other powers of the warlord are strictly martial. He isn't firing about divine light. Unless the cleric has no wisdom, the cleric is doing MORE healing than the warlord with the "generic leader healing burst effect". The cleric and martial each have healing as a level 2 utility. The clerics is daily, but doesn't use up a surge, obviously magical. The warlords is encounter, but is almost indistiguishable from getting 10 on a heal check to give someone their second wind ... the only difference being it can be in addition to the second wind. In this case the warlord is just slightly more skilled at using the heal skill than other members in the party, very "mundane". His main surgeless healing involves spending action points ... which require you be concious and aware of the warlord.
So, it ultimately comes down to either you can nerf a power, because the way you choose to interpret the power, it doesn't make sense, or you could try to find a way to make the power make sense, and thus the class can work the way it's supposed to. It's probably the use of the word "word" that is the biggest problem. Just call it "being awesome" ... the warlord heals his allies through sheer awesomeness. As long as they are within 25 feet, than can feel, at their very core, how awesome the warlord is and thus regain conciousness.
Ultimately, until you are dead you are either concious or unconcious. "Dying" means that you are at risk of death, if you fail enough death saves. This is different than dying in the real world which can mean either that you need medical attention/first aid quickly, or it might mean that there is nothing that can be done. In D&D it means there is chance you MAY die. In the real world, you will most certainly die without intervention.
Considering it's possible to get up without any outside help [rolling a death save totaling 20+] you obviously are able to regain conciousness at any time. How is it different to roll a 20 than to have the warlord someone say something that "gets through" and you regain conciousness? Both are entirely "martial/non-magical" ways that someone goes from dying/unconcious to concious and back in the fight.