The problem here is your premise that assumes that the warlord was healing actual blood loss and physical health, when in fact he is healing moral, energy, etc. The cleric can also very well be healing abstract wounds and not strictly open gashes.
I know it's easier/sometimes funner for the DM to say "the arrow hits you in the knee" but the fact is that that wouldn't be very representative of actual combat where an arrow to the knee would incapacitate you and lead to a whole new set of penalty mechanics.
Anyways all to say that HP have been an abstraction since long before 4e, most of you had just never really taken the time to think about it is all.
I wouldn't say they have all been an abstraction in previous editions because when a cleric healed you it was assumed that he was actually closing your wounds. When you would rest it was assumed that there was some bandaging going on but if you took massive amounts of damage, you would have to wait a long time if you didn't have a cleric or potions to heal you.
Now what the Warlord and Healing Surges did was cement that abstraction to a point where it started to seem a bit silly.
Healing Word Cleric Feature
You whisper a brief prayer as divine light washes over your target,
helping to mend its wounds.
Encounter (Special) ✦ Divine, Healing
Special: You can use this power twice per encounter, but only
once per round. At 16th level, you can use this power three
times per encounter.
Minor Action Close burst 5
(10 at 11th level, 15 at 21st level)
Target: You or one ally
Effect: The target can spend a healing surge and regain an
additional 1d6 hit points.
Increase the amount of additional hit points regained to 2d6
at 6th level, 3d6 at 11th level, 4d6 at 16th level, 5d6 at
21st level, and 6d6 at 26th level.
Here is the cleric's Healing Word power from 4th edition. Now Healing Word says that it uses divine light to mend wounds.
Inspiring Word Warlord Feature
You call out to a wounded ally and offer inspiring words of courage
and determination that helps that ally heal.
Encounter (Special) ✦ Martial, Healing
Special: You can use this power twice per encounter, but only
once per round. At 16th level, you can use inspiring word
three times per encounter.
Minor Action Close burst 5
(10 at 11th level, 15 at 21st level)
Target: You or one ally in burst
Effect: The target can spend a healing surge and regain an
additional 1d6 hit points.
The amount of additional hit points regained is 2d6 at 6th
level, 3d6 at 11th level, 4d6 at 16th level, 5d6 at 21st level,
and 6d6 at 26th level.
Now here is the Inspiring Word power from the Warlord in 4th edition. Now it states that this is used by giving a PC words of encouragement to help them heal. Now it sounds to me like the Warlord's words actually have some kind of supernatural power much like the Bard. Now if this is not the intention and the Warlord's Inspiring Word is meant to give that player courage in order to get them up and keep fighting because his wounds are abstract then there is a bit of a disconnect.
If it's the latter then here is where I have the problem. Let's say you have a Cleric and a Warlord in your party. You have lost a lot of HP and you need to regain some. Well the cleric says that he is coming to help you but something happens and he needs to help someone else. The Warlord then says that he would be able to help you instead. Now if the Cleric was coming to help you would your HP loss actually be wounds but suddenly turn into abstract wounds now that the Warlord is coming to help you?