Subclasses lack the mechanical heft to be more than a part-time warlord. You know, a little bit shoutey. Not really, really shoutey.
If subclasses had the ability to do things like steal the base class "extra attack" feature, they'd have the heft.
You can see what a warlord subclass has the room to do with the "purple dragon knight".
What more, in 4e, the same class covered:
1) The tactical genius
2) The battle-hardened sergeant
3) The waif of a girl who keeps on getting into trouble
4) The dashing young idiot everyone wants to follow
5) The elf lord who you can't help but obey
Imagine a Brash Idiot fighter subclass.
Bravura Precense
Starting at level 3, when a Brash Idiot fighter spends an action point to take the attack action, any one ally who can see or hear you may spend a reaction. If they do so, and at least one of your attack hits, they may make a weapon attack or move their speed. If at least one of your attacks miss, they grant combat advantage to all attacks until the start of your next turn.
Bravura Attack
At level 5, instead of the Extra Attack feature, when you take the attack action you may choose to attack Brashly. If you do so, the enemy can make an attack back at you as a reaction. If they do so, you can make an weapon attack on them at advantage, and one ally who can see or hear you can spend a reaction to make a weapon attack attack on them.
Rub some dirt into it
Instead of gaining an ASI at 6th level, when you use your second wind, all allies may spend up to half (round up) of their unexpended HD and gain that many temporary HP. At the start of each turn while an ally has these temporary HP, they lose 5 temporary HP and heal 2 points of damage.
No Attack is Wasted
At level 7, when an ally takes an action with an attack roll, and every attack roll misses, as a reaction you may make a melee weapon attack on any one of the targets. If your attack hits, your ally gains advantage on their next attack on the target before the end of their next turn.
You may do this up to your charisma bonus times (min 1), and then not again until you finish a long rest.
Charming Idiot
At level 7, during a short rest you can tell an idiotic tale and make everyone laugh. With you that is. All allies who spend HD during this short rest can reroll any odd die roll, but must keep the result.
Dumb, but Lucky
Starting at level 10, whenever you roll an odd number of a d20, you may choose to reroll it, but you must keep the result. You may do this a up to 5 times, minus your intelligence bonus, (min once) before taking a long rest.
Bravura Attack
Instead of extra attack at level 11, now if your ally's attack is triggered by Bravura Attack and they spend a reaction, they may take the attack action (not just attack once). In addition, if your enemy refuses to attack back, they must make a wisdom save (DC 8+proficiency+charisma) or all attacks on them have advantage until the start of your next turn.
Can't count to two
At 14th level, instead of gaining an ASI, you instead can use your second wind twice before taking a long or short rest.
Give 110%
At level 15, when an ally who can see or hear you rolls a HD and it lands on an even value, the HD is not expended.
Top This!
At level 18, whenever you do an attack, or attribute check, or save the first time any ally who can see or hear you who does an attack on the same target, or makes the same attribute check or save before the end of your next turn has advantage on the roll. If the same effect causes more than one ability check or save at the same time, you are presumed to have gone first for the purpose of this feature.
Bravura Attack
At level 20, two allies can spend their reaction to take an attack action if the enemy attacks you back.
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I'm not that happy with it, as it still isn't Bravelordy enough. Not enough Cha based stuff. Not enough leading utility.
It does have HP support, "hey, hit me" abilities, wields barbarians as its primary weapon.
