It does beg the question (in conjunction with "let's make Ranger as a Fighter subclass" thread and kind of intersecting with the "ideal class organization" thread) can the game be complete and satisfying with the game offering:
Fighter (full/base class)
--Paladin subclass
--Ranger subclass
--Warlord subclass
(presumably people would want to keep --Eldritch Knight subclass for the psuedo-ftr/mu multiclass)
I think the answer is clearly, yes. It could be a complete and satisfying game, allowing for whatever character broadness within each and/or layered by other elements (backgrounds, etc...).
But it would undoubtedly get certain persons/playstyles who have grown up with "full classes for every character concept," and/or "every corner case permutation I can come up with must needs be supported" up in arms.
Edit: I forgot the Barbarian! So...
Fighter (full/base class)
--Barbarian (Con.ftr, + Rage, extra attacks, more damage, no magic, survival/endurance skills)
--Warlord (Cha.ftr, + Inspire, extra attacks, more hits via others, saves for others, no magic, interactive skills)
--Eldritch Knight [don't love the name] (Int. ftr, +limited Arcane spells & powers, more offense and defense through magic)
--Paladin (Wis. ftr, +limited Divine spells & powers, more offense & defense through magic)
--Ranger (Dex. ftr, +limited Nature spells & powers, more offense & utility through magic, nature & stealth skills)
/Edit