What you can't do is recreate the 4e warlord. A 5e Warlord isn't going to resemble a 4e Warlord any more than a 5e cleric resembles a 4e cleric. They are completely different creatures.
A big reason warlord discussions often fail to go anywhere is that the warlord is, in some cases, just a shibboleth for "I prefer how 4e did things." So, the convo just becomes grousing about how 5e doesn't have 4e's model of martial powers, or how 5e doesn't officially support a purely morale vision of hit points, or how 5e's Fighters "can only do one thing," or how 5e doesn't cleave tightly to 4e's role grid, or how 5e resists option bloat (especially at low levels), or how 5e favors big effects rather than granular options. The warlord had a lot of tethers to 4e's systems, and the transition away from many of those systems is going to leave any 5e version of a warlord quite a different beast. That can be OK, if what you're looking to do is play a character who fits a warlord archetype - who is an inspiring leader and brilliant tactician. There's an abundance of options in official 5e to play a character
like that. There just isn't much of a way to get back to some of 4e's assumptions.
Weirdly, this
is similar to some of the problems with the psion (though change 4e for 2e/3e). At the core is a 5e design choice that I think is basically a good idea: they're reluctant to reinvent the wheel, mechanically.
So, like,
healing word. That spell is very warlord-coded. It's literally a shout that restores hp. But, the flavor is "you're casting a spell." So a certain segment of warlord fans are never going to be happy with using that as part of their inspiring commander. If you duplicated the effects of casting
healing word (and maybe a bunch of other healing and restorative spells), but called it an inspiring shout or battlefield medicine, you might get some people on board. And, after a few rounds of this and adding some more class features (let's add
command to the list of nonmagical spells, oh, and here's a 4e power I really liked that could make a good nonspell, too), congratulations, you've basically recreated the core of cleric or the bard or the paladin or whatever, and all you've done is file the serial numbers off and call the magic skill/inspiration/narrative juice/etc. And it still wouldn't satisfy people who want more low-level options, for instance ("That's not a real warlord, look, I can't XYZ at 1st level in addition to other things, this is just proof 5e is bad at this, if only the devs would realize this...").
There isn't a lot of apparent appetite in the 5e developer tower to spend their limited budget and pagecount for the year on something that is basically "the bard, but replace magic with inspiration, disappoint about 1/3rd of the people in the process, and maybe open up the hit point debate for a brand new generation." And I can't really blame them for that. The risk/reward just doesn't pan out. I'm sure their surveys have given them this feedback, too - the juice hasn't been worth the squeeze.
You can see the same phenomenon at work with the psion. There's spells out there that do what we'd expect a psion to do, but the flavor is a little different. It's "you're casting a spell," not "you're using MIND POWERS." We could file the serial numbers off of several spells and throw them into a class and get a lot of people on board. But, then we have recreated the psion or the wizard or the warlock and all we've done is say "It's not
that kind of magic!" And we still would leave people who wanted something more radical out in the cold ("Where's my power point escalation mechanic?!").
I'm sure if their surveys told them that what we want is, idk, four versions of the warlock with subtly different magical coding (arcane! martial/narrative! psionic! and here's a version with runes, too!), they'd give it to us. And, I don't think the warlord (or psion!) fans are wrong for not being satisfied, for whatever reason they have for not being satisfied, even if the reason they're not satisfied is only because they really liked how 4e did things when it came to warlords, and 5e just will never be the same. That's valid, and one of the limits of 5e is that it won't ever be 4e, or 3e, or 2e, or 1e. It's not the same and won't ever be the same.
But I do enjoy playing my college of swords bard as an inspiring leader whose words can lift armies and curse my enemies. And I enjoy playing my battlemaster fighter as an action economy thief who can lock down big threats until they decide to pay attention to him. And I enjoyed playing my alchemist artificer as a non-magical healer who brewed medicinal tonics in the heat of combat. And I enjoyed playing my devotion paladin as a tactical genius / blowhard who always thought he knew what was best for people and who enjoyed using his party members as his weapons most of all. Just like I enjoyed playing my 4e warlords as team dads, lazy drunken bosses, and literal princesses.