As always, by this logic D&D should have only two or three classes.
What is unique about the Paladin that isn't represented by the Cleric or the Fighter?
Mechanically: Smites, special mounts, weapon/armor training.
Thematically: Paladins are chivalrous crusading knights, an elite cadre of noble bearing. Clerics are servants of the gods, ministers and healers and holy sages.
A paladin is more than just a cleric with a sword. A cleric is more than just a paladin without a horse.
For that matter, what is unique about the Cleric that wouldn't be represented by a multiclass Fighter/Wizard who talks about god a lot?
Mechanically: weapon/armor skill, different spell effects.
Thematically: Clerics are given blessings by their deities to work the gods' will in the mortal world, wizards wrest secret power from the very core of reality and twist the world to their desires, fighters are masters of combat and battle whose skill in slaying their adversaries in unmatched.
Clerics are more than fighters-who-also-cast-spells. Wizards are more than spellcasting mechanics. Fighters are more than the ability to use heavy armor.
What makes the Ranger and the Monk deserving to be classes of their own, rather than Fighter/Rogue combos with some focus on woodland skills or feats spent on unarmed combat?
Mechanically: ki, TWF/archery focus, animal companions, pseudo-mystical powers like disease immunity, nature magic.
Thematically: Monks train their bodies and minds for enlightenment and self-actualization, not for combat and war. Rangers are not defined by battle and combat, they are defined by their role as inhabitants and guardians of the wilderness.
Monks are more than just unarmed attacks. Rangers are more than just flurries of scimitars. Fighters are more than just weapon proficiencies and a high attack bonus.
For some reason you object to smashing the Barbarian (ie. the "angry fighter") into the Fighter because that would make it too broad, but smashing a healer into the Fighter is a-ok. That strikes me as an odd double standard.
Mechanically: Rage, speed, sheer bloody toughness.
Thematically: Barbarians are defined by their self-sufficiency and their uncivilized origins, tapping into a character with an alien mindset. Fighters are defined by combat and war, tapping into a character of determined toughness and superb combat competence.
Barbarians are more than just "angry." Fighters are more than just high HPs and a big weapon.
Furthermore, to actually answer some of your questions, the difference between a Warlord and a Bard is that one of them is a spellcaster and the other isn't.
Debatable. And academic, especially coming from 4e where the difference between "it's magic" and "it's not" is a keyword or two.
The Bard has never been a non-magical healer. That's not just a semantical issue, it's a statement about how the game world works. For many people, the Warlord is a favorite precisely because it takes D&D's presumptions about healing into a direction that they want it to.
Non-magical healing doesn't need to be linked to any particular class. If that's a thing you want, there's no reason that it needs to be tethered to the Warlord.
TwoSix said:
Part of the appeal of 4e was the degree to which it embraced being innovative while staying within known D&D tropes. I'd have a much higher opinion of Next if it simply also tried to be innovative, even if it moved away from 4e-isms. The high point of the playtest for me was the Sorcerer packet, because that was actually something new and different.
I wonder if part of what they learned from that is that the D&D crowd is actually quite conservative about their game -- that the target audience actually doesn't want drastic changes and new hotness just for the sake of there being new hotness. Dwarf fighters and elf wizards never go out of style, right?
I imagine the innovations may be more likely to occur in distinct, self-contained packages that don't so much worry about turning D&D as a whole into some designer's fantasy heartbreaker as much as give you new stuff to do, if you want it, or you can ignore it if you're that guy who has been playing the same dwarf fighter for 30 years and is quite happy there, thankyouverymuch.