While this point about warlord design not working with 5e is entirely true it’s not a problem that is exclusive to warlords, and you’d probably have just as much trouble transferring any 4e class directly to 5e or trying to put 5e class design into 4e ones even, it's like porting 2D mario's code into a 3D game and wonder why you're having issues, it's because it's not designed to handle in that environment.
The point being, mechanically warlord was designed for 4e but there’s no actual issue in the fundamental concept of a warlord being in 5e, just in trying to exactly replicate how it worked and existed in 4e, and like you said, trying to shoehorn it into a fighter subclass power budget.
You make a good point. The main difference between the Warlord and many other class concepts is that other class concepts usually have a reasonably long history in the game, going back at least to 3e and usually longer than that. So when they want to make a "Cleric but not like the one in 4e", there are plenty of models to rely on. But "Warlord but not like in 4e"? That's a tough nut. The one exception is the Warlock which was a mid-3e invention (Complete Arcane, IIRC), but the Warlock is easy to figure out as a "caster but" class.
And yes, there were 3e antecedents of the Warlord, but those were done in the context of 3e which was also a highly tactical system. Also, the Marshal kinda sucked – it basically just let you provide a passive buff to one minor and one major thing, and grant extra moves a small number of times, and notably couldn't heal. You also had the Devoted Spirit and White Raven disciplines in Tome of Battle, but again: highly tactically focused system.
you can, they just manifest differently, i suspect your issue here is that you have an overly narrow perspective on what 'tactics' must be and thus 5e fails to fit your definiton, but what are abilities like commander's strike, distracting strike and maneuvering strike if not representations of tactics in 5e? i'm sure there are many more other abilities that exist that i cannot list off the top of my head that are also designed to serve the place of tactical skill.
This is similar to the issue with psionics. There are classes in 5e that use psi-like abilities, but they are all variants of other classes, and there's no one-stop shop for psionics the way the wizard is for arcane casting.
This is D&D general so I figured Pathfinder was fair game. I was honestly asking about the commander, not saying warlord shouldnt be a thing.
The Commander is in a bit of a limbo at the moment as it will be in an upcoming book. There was a playtest, but that provided a fairly limited view of the class.
The main issue with it (as a warlord) is that it's a PF2 martial class, and as such does not have any resource management beyond actions. Almost all their abilities can be used as often as you like as long as you have the actions for it. That means that they are necessarily limited in what they can do – anything they do have to be balanced to do at will. And that means they don't get to do the
awesome stuff. Also, with the exception of Valkyrie's Charge which they can learn at level 19, there's no in-class healing or even temp hp.
I'm sure it's perfectly cromulent at what it's attempting to do, but that's not the thing I want.
"Emanation" was a game term in 3e D&D. Pathfinder copied it directly from the SRD.
There's a minor difference between a 3e emanation and a PF2 emanation. In 3e, the point of origin of an AOE is always a corner, so for a small or medium character it will always be a bit skewed. That is, a 5-foot emanation in 3e will cover four squares, including the source. In PF2, the emanation uses the whole source as a point of origin, so a 5-foot emanation emanating from a small/medium character will cover nine squares, with the source in the center one. That means that emanations coming from larger characters will be slightly bigger.