It's almost like you are trying to argue, "if an EK was supposed to fulfil the concept of Wizard then he wouldn't mechanically do so", which is a sentiment I agree with. But we know that an EK was never supposed to fulfill the concept of Wizard. The Battlemaster was supposed to fulfill the concept of Warlord. That's not the same at all.
So, why does my criticism here of that point not make sense to you?
You keep
saying this is what the Battle Master was supposed to do. I reject that argument, both in theory and in practice. I've already covered the practice side, and it seems you care about the other. So: On the theory side, I genuinely do not believe the Battle Master was ever "meant" to be a
Warlord. It was, however, pretty clearly meant to capture the feel of a
4e Fighter. (Remember that the "baseline" 4e Fighter was called the
Weaponmaster subclass, which is far too similar to be mere coincidence.) When the designers got backed into a corner because it took them forever to settle on the shape the Fighter class should have (seriously, it wasn't until like the final or penultimate document that the Fighter even
started to look like it did in the published PHB), they had to resort to what measures were available.
Now, the Purple Dragon Knight/Banneret?
That I could at least admit was specifically supposed to be a Warlord--it even uses the word "warlord" in some of its text (e.g. "Banneret serves as the generic name for this archetype if you use it in other campaign settings or to model warlords other than the Purple Dragon Knights.") It is also about as close to "bad" as you can get for a subclass without actually BEING bad--that is, its features are painfully mediocre and limited, and (IMO) don't really deliver on the concept of a warrior who leads others in battle.
The Battle Master is almost purely focused on doing tricksy things with weapons. It's not a Warlord. You can kinda-sorta-ish kludge part of a Warlord out of one, but it was very clearly intended for a different function--or, as I said, it's the EK of Warlords, where it's
mostly a Fighter but has some Warlord mechanics stapled to it.
So I think the question we are struggling with is - 'what do we do when a concept in the books have poor mechanical representations. Do we:
1. Create a new class/subclass so that the concept can have better mechanics?
2. Adjust the mechanics of the existing class/subclass so that they are better?
3. Live with the crappy mechanical implementation of the concept?
There are pros and cons to every answer. What I'm not seeing acknowledged are any cons to the 1 approach which is the most advocated approach on this thread.
Well, here's my thoughts.
Option 1, pros: the freedom to add things that are missing, and (for classes specifically) to not be limited by how much power a subclass is allowed to have; ability to tailor the solutions narrowly and specifically to what is needed
Option 1, cons: reduplication of effort/lack of parsimony, more difficult to balance (because, e.g., a character could MC BM/Warlord)
Option 2, pros: Can (in theory) be published as errata, makes the smallest possible changes while still changing
something
Option 2, cons: Unlikely to
actually be published as errata, unable to create new mechanics or fill holes that already exist
Option 3, pros: Requires zero effort and avoids any controversy about errata or lack of parsimony
Option 3, cons: Fails to address the problem.
Does that meaningfully address your concerns about failing to consider negative aspects of a solution? I do not consider absolute minimalism a virtue in design. Logical parsimony is only virtuous as long as it does, in fact, actually cover everything it's supposed to; remember that Occam's Razor is not "always use fewer entities," it is "entities should not be multiplied unnecessarily." Newton's theory of gravitation is
simpler (dramatically so) than Einstein's theory of general relativity, but we use the latter and not the former due to relativity covering more of the facts.
I am arguing, here, that trying to make the Battle Master Fighter cover
both the Mighty Thews(/Agile Archer, I guess) AND the Inspiring Captain archetype is leaving both things under-served. That we are not seeing parsimony, but rather deficiency; not frugality, but miserliness.
A wizard limited to level 1 spells is still conceptually a wizard. Scaling can still be a mechanical issue. But it's not a conceptual one. The 4e Warlord is conceptually in 5e, it's mechanics for it are just crap.
Again, I disagree--mostly because the Battle Master, as I argued earlier, is far too
personally capable. The Warlord concept is not merely someone who CAN choose to inspire allies. The Warlord concept is someone who NEEDS to coordinate and strategize with allies in order to get things done. Now, this does not mean having NO combat capability without an ally--the Warlord could do some butt-kicking on her own. But it should mean that the
best butt-kicking they do is either in direct combination with allies (e.g. Bravura Warlords who give allies risky opportunities), coordinating the whole team's movements to maximally exploit terrain (Tactical Warlords with repositioning, initiative, etc.), or dredging up those hidden reserves we all have but never tap because of self-protection instincts (Resourceful and certain other types of Warlord).
In general, the best thing a Battle Master can do is
just attack more. It's going to be pretty rare, for example, for
Commander's Strike to actually do better than the BM just attacking again.
Distracting Strike isn't...the
worst, but is pretty narrow--a chance for a chance for a good thing to happen. Rally is pretty much just bad, since it can't actually
heal anyone. (Like...for real, even granting 6d12 healing at level 18 to every party member once per short rest is NOT that powerful, and doing that means you did LITERALLY nothing else special. A Life Cleric can do that easily, except that they can target just the people who need it most, and they
still get all their spells on top.)
Maneuvering Attack is probably the only "Warlord-type" maneuver that actually does more or less what a Warlord would do.
And...that's literally it. Those exhaust the "Warlord options" for the Battle Master. It's not just a matter of no scaling; it's a matter of you get only four Warlord-like things you can
potentially do, and most of them are just not worth doing when you could instead, y'know, just do it yourself. Which is the fundamental problem of the "Fighter-as-Warlord." To be a Fighter,
any 5e Fighter, you must be good at kicking butt all by yourself. The Battle Master simply adds a layer of "oh and you can also potentially boost an ally along the way" on top.