I think most fans are fine with "see and hear" for most of the warlord abilities.
I doubt it. I am not.
IMO, "See" is an unnecessary restriction. The ability to see is not a factor - or even mentioned - in any narrative of inspirational recovery I've seen or read. I can however, imagine inspiration purely by voice, even in complete darkness.
"Hear" should absolutely be a requirement though. However, I disagree that an unconscious character can't hear. Unconscious characters are "Unaware"; but the subconscious mind is by definition "Unaware", yet still "hears."
"Not able to Hear" is the Deafened condition.
I would eliminate "See" entirely. I wouldn't even require "Adjacent"; though I might allow for a bonus when adjacent (or penalty when not adjacent - I've been playing around with the idea of inspirational recovery requiring a saving roll).
From what i've gathered, we can appease the most people by...
Inspiring word: An ally who can see and hear you can spend a hit dice to gain X HP.
First Aid: You can take an action to perform first aid on an unconscious creature. They regain 1 HP. A creature can only benefit from this once per short rest.
Resuscitate: You can use first aid on a creature who died within the last minute, bringing them back to life.
The rest is mitigation abilities, with a sub-class that boost healing further.
Which i think will satisfy most people.
Appeasing people to the point that the class is no longer a Warlord renders the entire endeavor useless.
Developing a Warlord is for the benefit of Warlord fans, and not for appeasing those that aren't.
Appeasement is a horrible premise and a terrible design philosophy.
It would kinda suck to be in a martial party, get petrified, and need to run off to find a cleric. But it's also kinda hard to justify curing a petrification non-magically.
One of the features of a Warlord is to be able to run a "non-magical" game/group - not necessarily an all "martial party."
A game that had the possibility of petrification in it is most likely not a non-magical game. If the DM decided to use petrification anyways in a non-magical game, it would require a non-magical premise - a disease or toxin for example.
I don't recall seeing Warlord fans expressing a desire for a Warlord to heal disease or neutralize toxins, nor have I heard a narrative or trope where an inspirational effect neutralized disease or toxins. (Nor have I seen Warlord fans wanting a Warlord class to be able to reverse petrification.)
I believe that would fall under the premise of the Healer Feat - using a Healer's Kit or Herbalism (or equivalent). Maybe an adventure hook to find a rare flower or plant, or a knowledgeable enough Healer/Herbalist. But not as a Warlord ability.
Yes, the idea of the Warlord as replacement for the Cleric has been expressed, and to a certain extent it is part of the concept - but only to an extent - only within the narrative premise of a Warlord. A Warlord, narratively, doesn't do "everything" a Cleric can do.