Zardnaar
Legend
Yeah, you should. If you were going to do that in the first place, then that would’ve been perfectly viable. Instead we have 5 flavors of the same fighter with various subclasses and 6 flavors of the same spellcaster with various subclasses.
That should definitely have been 4 very different classes with a whole grip of subclasses that might be viable on any base class. But whatever.
The classic D&D classes are heavily based on things from myth, literature and history or some combination of all of the above. Ranger= Aragon, fighter= Knight/gritty soldier, Paladin=Knight ideal, Cleric= templar etc. Hell a few classic cleric spells are from the bible.
The warlord is weak in literature at least in the way 4E had it. Sure there have been things like Fighter generals (Caesar, Alexander, Richard the Lionheart etc), but that maps more to things like the AD&D fighter with followers as a core of an army than the 4E warlord.
Its easier to find other things as well, Merlin=wizard, Morgan Le Feyy sorcerer or warlock, Arthur Paladin or Fighter.
The Warlord is not drawn from similar sources it was purely a gamist creation for the 4E rules system as another leader type for clerics. It was not an organic creation as such perhaps derived from the 3.5 Marshall which was basically designed for the D&D miniatures game (designed by Heinsoo and Tweet). Quite a few D&Disms also date back to the classical/biblical world (polymorph, magic weapons to hit, clerics and cleric spells etc). The names also a problem although its not unique there (Ardent, Warden, Duskblade,etc). You get a basic idea for a D&D class from the name at least the PHB ones if you are remotely familiar with pop culture, myths, literature etc.
You could boil the game down to 3 or 4 classes (probably 4 minimum if you merged cleric/mage you may no longer be playing D&D). For a generic d20 game Warrior, Expert, Magic would be your 3 classes I suppose.