I've been saying it's all in the fluff this whole time! (Fluff that's necessitated by the fluff of "non-magical, non-supernatural", even.)
I
bolded the bits I find objectionable in the list you posted:
You trick your adversary into making a tactical error that gives
your comrade a chance to strike
Step by step, you and your friends surround the enemy
You slam your shield into your enemy, bash him with your
weapon’s haft, or drive your shoulder into his gut. Your attack
doesn’t do much damage—but your anger inspires your ally to
match your ferocity
You trick your adversary into making a tactical error that gives
your comrade a chance to strike
Like a leaf caught in the autumn wind, your foe is driven by the
flow of battle. Your fierce attacks force him to give ground.
You land a ringing blow against your foe, inspiring a nearby ally
to strike a blow of his own
Under your direction, arrows hit their marks and blades drive
home.
You lead the way with a powerful attack, using your success
to create an opportunity for one of your allies. Each of your
comrades in turn seizes on your example and begins to display
true teamwork.
A timely critical hit affords you the opportunity to rally a wounded
ally.
You direct your ally’s charge, allowing him to strike a deadlier
blow and push his foe backward.
You fortify your allies with a few words of encouragement.
Despite the chaos of battle, you see a golden opportunity for an
ally to make a surprising attack.*
You level your weapon at your enemies and utter a grim threat
that leaves them fearing for their lives. With great words, you
turn yourself or an ally into a battle-hardened juggernaut.
Each of those things suggest, to me, that the Warlord is causing my character to do or think something that I haven't chosen myself. That's what I mean by loss of agency.
*The one I marked with an asterisk bothers me for a different reason. Ok, so the Warlord sees this opportunity and then what...conveys it in words? "Ralphie! His chainmail underwear slipped down, now's your chance!"
I can totally buy that one character might see this and another one doesn't, and that sharing the information would be useful. But why is that an ability, and not just an Action that anybody can take? By restricting it to one class it suggests that only that class can see opportunities, opportunities that are apparently simple enough to both convey and understand in a couple of seconds. That, in turn, suggests that other classes are unable to see those opportunities, since they apparently are unable to convey them. And it kind of sucks to think that my highly trained warrior or rogue is such a novice that he doesn't see these things.
Hmmm. Maybe the fluff that could alleviate that is something to the effect that the Warlord has honed the ability to watch multiple things at once, so he can keep an eye on what everybody is doing without dropping his own guard. Whereas other characters might, for example, lose their Dex bonus or something (ok, not applicable to Plate wearers, but whatever) if they tried to do the same thing.
Ok, maybe I'm ok with that particular ability after all. My concern is that it not sound like "The Warlord knows more about my job than I do, so he needs to coach me."