I think the crux of the matter here is that 5e doesn’t play like 4e.
It’s a boatload more simplified in combat so as to prevent the game from requiring miniatures/battle mats.
Characters just don’t have as many powers as they did in 4e. Spellcasters might, but even there the arcane spells/divine prayers/primal evocations/psionic powers have been codified again into a single Spells chapter, so different classes access the same powers (so fewer unique magical powers over all).
It’s a different game. I love 4e, but not everything that was a Class in 4e is going to be a class in 5e. The editions have different ideas of what it means to have a class. In 4e, a Swordmage could be its own class, but while one could build an arcane-fighter halfcaster, it’s very hard to find a broad flavour there that has lots of room for subclasses of differing ideas. It works well enough as subclasses for various different casters/noncasters.
Warlord is an example of a class with a really cool mechanic but not much story difference for what makes them not a Fighter, and what makes an Inspiring Warlord different from a Tactical Warlord different from a Bravura or Resourceful or Skirmishing or Insightful one.
That’s why I brought up Battle Master and Banneret Fighters, Mastermind Rogue, the Superior Technique Fighting Style, and the Martial Adept feat. The Warlord is a concept that fits into different wings of different classes. A Bravura Warlord inspiring with courage from the frontlines functions differently from a LazyLord moving around allies like chess pieces and granting them attacks, functions differently from a skirmishing fighter leader functions differently from a master of tactical abilities.
We now have a fourth alternative access into that tactical system, so there’s lots of ways to capture the flavour of a 4e Warlord within 5e.
Want to play an Insightful Skirmishing Warlord? Take Archery or Thrown Weapon Fighting Style alongside Battle Master or Banneret. Have a higher wisdom score. Multiclass Scout Rogue or Ranger if you’re really seeking that Aragorn-like character.
But you’re fooling yourselves if you think 5e can ever accurately reflect the specific tactical game play of 4e. The game doesn’t try to do that and it’s ill-suited to shoe-horn the feature in.