I realize you did mention it later, but, do you have the same problem with paladin?
Paladin is a D&Dism, yes, but at least it is a disused word they're redefining (Charlemagne's knights don't get referenced much), not one with currency and meaning in the here and now, appearing on the headlines.
And just because a D&Dism or three exists in the core is not carte blanche to alienate D&D further from solid fantasy archetypes. D&D is popular despite these, IMO, not because of them (and how people substitute "holy white knight" in their head for paladin and "fighting healer priest" for cleric, generally. The weaker archetype is the cleric, because it borders on incoherent, with little in the way of mythological touchstones. Warlord even lacks a basic archetype, the closest being "fighting cheerleader" or "drill sergeant", neither of which float in an adventuring party).
Get as D&Dism and world-specific as you like in specific settings, go beserk, just leave the core relatively accomodating of fantasy worldbuilding in general, not just WOTC's idea of a cool fantasy world. Strong, general fantasy archetypes support that; weak, contrived or world-specific ones damage it.
The evolution of the "warlord" probably goes something like this:
Bard in AD&D 1E appendix, proto-prestige class. Super-tough, celtic-flavoured and legendary, reflects mythological bard to a degree. Strong archetype.
Rogue needs sub-class for design symmetry in 2E. Bard gets promoted, loses way, becomes musician. Archetype becomes jack-of-all-trades minstrel, about as appropriate as a jester core class.
3E design team tries to fix bard. Becomes poster boy for their ideas on spell failure in armour.
3.5 tries to fix the damned-if-you-do-damned-if-you-don't relationship the class has with spell use and armour.
4E design team agrees with Order of the Stick that lutes in a dungeon is ridiculous. Tries to fix bard by removing instruments, renames Marshal to Warlord. Forgets to include a viable archetype, being focused on cool crunch possibilities.