If only there was a Warlord class! Fie upon these Fighters, Rangers, and Paladins! None of them express the demonstrated leadership abilities of this character adequately!" ? I submit that the realistic answer is very near 0.
The issue at stake is a class based system in which inclusions in one area usually exclude inclusions in others. This is the basic problem (without taking the spellcasting to remove the problem) with the 3.x paradigm of Fighter / Rogue / Caster. If you are good at casting you were excluded from being good at fighting. If you were good at fighting you were excluded from being good at skills or casting. The balancing mechanic of the class based system is that if I add A to the triangle on one side (fighting, skills, casting), I have to remove the "equivalent" of A from one, or more of the other sides.
The reason there have customarily been dozens of classes in the game is because of all the other (customization features) additions that the game makes. Instead of poorly depicting a class concept by tacking on multiple different other concepts from the customization features, a new class is designed to handle that in balance with the other existing classes, and still have the opportunity to tack on customization features as wanted.
A fighter in no other edition has ever had
mechanical underpinnings to inspire his comrades, tactically change the battlefield, maneuver his comrades, affect the action economy, allow saves, and shift the tide of battle. Most of these things could have been accomplished by spell casting in some way, but usually not by one class. The cleric had some, the wizard had some, and the bard had some.
When designing the new class system, by saying that you are rolling a particular class into another, what you are in effect doing is removing customization options at the most base level. Because you will be using your available customization options to emulate another class instead of selecting the other class and then customizing to taste.
What the 4e warlord introduced was an actual dimension to the game that had solid mechanical aspects, as well as narrative aspects, that were not magical, and that were balanced against the other classes (a fully developed class with class features). Leaving the additional aspects/customization features (backgrounds, themes, feats, skills and powers) still open for customization as wanted. Something the fighter never had in any edition before.