The system of division and utilisation of Command Points that I could
envisage being fairly useful/realistic does unfortunately seem to need a lot of micromanagement of results and tallying in the head (perhaps more suited for some computer-mediated system, such as a Turn Based computer game with partial automation/inertia of units), but I'll briefly outline what I thought.
A unit on its own as the "one thing" it can naturally do... No, actually
half a thing it can do[1]. Until it builds up a full point, it cannot change. Interference by an enemy (in a "no plan survives contact with the enemy" manner) zeros the tally, so if the enemy has an upper-hand and keeps harassing a unit continuously, they have no option to do anything other than hold/run/react in whatever way the general tide of battle forces them. When left alone for a turn (perhaps), there's a chance to gather their wits and execute an actual
planned break-out, counter-attack, stop fleeing or whatever.
(Some things may have to come before others, e.g. stopping running away before actually counter-attacking, thus needing more time to gather their wits. Evacuating an emplacement might require transitioning from keeping under cover to actually
creating covering fire in preparation to bailing out in an orderly manner, although "just running" (at the expense of any practical defensive measures, taking a non-random route away from their location, or just keeping themselves ordered enough in order to quickly dig in at a fall-back position) might be an immediate action, indeed perhaps an outcome of losing whatever 'morale'-type test is applied to them.)
A ranking commander, of some kind, adds to this if directly present. Different levels add different amounts, but not exponentially so.
Just having a five-star general and a handful of grunts, and they having superhuman capabilities and reaction-times is very much (as I'm sure you'd agree) very 40Kish. OTOH, unless there's other adjustments (if they were a 'killing general', e.g. some sort of Lord Kitchener character who might hold little sway with trench-weary and cynical troops, say) there'll be inspiration and practical experience behind the commands. "You, you and you, get that heavy weapon operational, you two, watch the flank approaches, the rest of you check your weapons and reload as necessary, they're going to be coming this way as soon as the smoke clears and I want us
ready for that. Medic, get yourself a cubby-hole for triage, and you know what to do if they break through our lines."
That's local control sorted, but there's always some form of remote communication available, as already said (although I'd have said WW1 was more a matter of field telephones (backed up with runners and riders of various kinds) rather than so much the heavy radio set, and there's
always been some variant on semaphore), and a unit has not just its own initiative/command points/whatever, but should be receptive towards commands from others.
There'll be two forms of command involved. Battlefield-wide ones and fine-control. When taking the overall commander's points, conveyed from the back lines, it should be a simple matter of his points, spread equally and undivided to all and sundry under his command. It may go through one or more communication links, but ultimately reaches the front-line troops at full force
all across the field, so at the local level you get something like: "The General says get ready to charge on his command... Charge! Over the top lads! Keep pressing forwards! Take the battle to enemy!". All assuming that the troops at the end of the command aren't under a current penalty (suppressing fire, bad morale, whatever), but the Orders From Above press the need and create an elevated level of rallying to the action.
But it's not all about the blunt instrument. You want some troops held back, perhaps. Or the general/equivalent already has everyone holding the line but needs to move a particular unit or two around to create a flanking manoeuvre. Here, the general's points are
split. If it's a command to just one unit to do one thing, with no complications, he can probably apply the full force of his authority to the end unit (via intermediaries, perhaps, but see below about that). "We've been given a mission by the Commander, guys. Those enemy guns need taking out and we're the best people to do that!" If ordering units on both sides to execute the appropriate movements to perform a pince-movement, though, then you can imagine he'd need to divide his attention somewhat to coordinate such a movement, and so there'd be greater difficulty. (Could include counter-commands so that while particular units charge, others are
explicitly ordered to hold their position, and not join in on the rush.)
Of course, there are subordinates to the overall commander, and intermediates. A lot of the point of having people like that is that you have people you can entrust to do the proper organisation and dissemination (c.f. the "all units forward" command, at each stage being relayed with no dilution of power).
Theoretically, there could be disruptions in this web of communication, so that part of the front-line does
not go over the top (the way-station for the orders has been disabled or suppressed by long-range fire or enemy incursions, or perhaps a clash of personalities or the incompetence of corporal in charge), but I don't know if that's worth modelling. But degrading the 'broadcast command' through trouble-spots could be possible.
If there's an ability to radio/semaphore/send-a-runner-to front-line troops, directly from battalion HQ (or equivalent), to by-pass the problem, then this would be dealt with under the split-commands rule. However, where command decisions are conveyed through sub-commanders, their own commanding points get added into the equation.
And, of course, the details of engaging the enemy at the front line is rarely the concern of the guy in charge
as long as it gets done. The simpler commands to "make it so" are passed from the (not necessarily fully informed) HQ unit at the back (or in the middle of their own
private skirmish, if things aren't going quite as they should) and the competence and awareness and actual capability of the middle-ranking officers is a definite factor. The equivalent of the fine motor control needed to safely move a heavy, but still fragile, vase from a table. The undiluted (other factors excepted) 'General order' is fine-tuned by the intermediate commands who make the appropriate splits/generalities to the way
they trickle down what they need to the units, and the unit commanders shape the way the front-line interprets these. Here the 'inherited' command benefit is not combined with the local guy's full command-load down each and every leg of his own areas of responsibility, but takes the command "Send the assault troops forward, with appropriate covering fire" and 'expends' his command on both the guys going 'over the top' (or equivalent) and the mortars/whatever that'll be staying put. The trickle-down benefits from the general order, while being penalised by the split specifics.
Which is probably where it 'gets' complicated.
Hence why I'm not sure it's a useful thing for TTRPGing. But maybe it can be simplified in some way. Whichever way, it would force one to balance the command structure. One 'big guy' sending overarching orders out through a wide-but-shallow tree of command would be able to put a lot of force behind "blunt force" orders, but have problems when trying to make finer control. A deep structure of command and control could give a lot of precision to the tactics employed, but potentially weakens the authority sometimes needed to encouraged actions to go ahead that way.
One thing I might add, from my extensive TTRPGing experience[2], though more to do with the overall design rather than the specific questions raised in the OP: don't make a high dice-roll good in some circumstances and a low dice-roll good in others[3]. Perhaps it's excusable that in one given system the morale needs you to roll under a value (thus the higher test value gives you better chance to succeed) but damage likes you to roll over (check against an armour value), but I've played systems where chance to hit is above, then the ability to damage is below, then criticality of damage is above, then... Well, YGTI... It's generally all
qualified, but (though I can't quote you chapter and verse at the moment) it all seemed like it had been set up and then qualified afterwards.
(Actually, there's one thing I
can highlight. While I admit there are grudging reasons behind the mechanism, the AP (armour penetration) of 40K, or at least the variant that I get asked to play, always seems to me to be counter-intuitive. AP1 being good, AP5 being bad. But then when you have to roll a weapon with
varying AP level, you'd like to roll low, right next to wanting to roll high when adding to the power of the shot to overcome the armour-level of the thing you're hitting. But I might not be playing the latest codex stuff (the other guy's in charge of the 'system'), so please feel free to ignore me if I've misinterpreted something.)
[1] Was going to say "two points needed to change objective", but I've changed my mind. Simpler (though equivalent) that a single point does that job, and reducing the background 'capability' to half. Other fractions are available, no doubt, if fine-tuning indicates they'd be useful.
[2] Mostly losing. It's experience, not
expertise!
[3] Saving for "Having
undershot your artillery, let's see how much damage you did... Awww, very little. Looks like your guys emerged almost unscathed from that little accident, after all." And there's always times when you'd actually
prefer your Warhound's damaged reactors to go critical and take out the enemies currently surrounding it, rather than just die on its feet.