El Mahdi
Muad'Dib of the Anauroch
...Why can he only do it twice per day? What exactly is stopping him from doing it over and over?...
Adrenaline hangover...

...Why can he only do it twice per day? What exactly is stopping him from doing it over and over?...
It does sound very good! I'd endorse this, specially if warlord healing and second wind become TempHP which disappears after the fight. To have the fighter "nova" and brutally end the combat sooner because he'd rather burn his extra THP than see them disappear, that would be totally awesome!
I think it would be interesting to see daily abilities tied into some kind of HP burn, since HP is already acknowledged to be "mojo" as much as it is actual health, let fighters take special actions at some kind of HP burn to represent exhausting themselves. Perhaps tie it in to Warlord "healing" of granting temporary hit-points, ie: more "mojo", that Fighters could then burn to use special abilities.
ACK! NO!
Anytime you burn health in a fight to do something, you create a "death spiral". Star Wars Revised showed this perfectly. You had to burn vitality to use the force, even to heal. Because fights were very lethal, you rarely did it in combat because even if you used a power to knock your foes back (force push) you lost hp. Star Wars fights turned into long-slogs of attrition punctuated only by how dumb the critical hit system worked (another topic for another day).
HP should only measure how many close calls you take before you die. Spending it to attack just means the fighter will spiral down faster than anyone else.
I hope the Warlord never shows its face as it was in 4e. I do not want some non-caster healing anyone or somehow making you move faster simply by shouting.
I don't have a problem with non-magical characters having daily powers. I take the "daily" as a game or genre abstraction, not as a literal simulation of a physical reality.
I don't agree with you that a fighter must be doing damage every round in order to be "pulling his weight." If a wizard spends his action casting a charm spell or some other debilitating effect rather than shooting a fireball, that's still a good use of his turn even if it doesn't deal damage. The same is true of a fighter tripping, disarming, etc. He's putting the enemy in a compromising position that may greatly reduce its effectiveness, make it more vulnerable to future attacks, prevent it from fleeing or repositioning, etc.
I disagree, it's the easiest way to balance the fighter with the other classes and keep it unique. Having the fighter make an extra attack every time it gets around to him isn't going to significantly slow down the combat anymore than having the wizard roll more dice for his fireball or the cleric rolling more dice for his healing. A turn based resource pool is also the easiest thing to keep track of.
So this won't happen, but I was thinking about a mechanic for this that might work, and is somewhat based on real life... Im a martial artist, a lapsed one anyway, and in essence the more advanced my opponent, the more difficult it is to land a complex blow.... That said
What if the powers list was like the clerics spell list, a series of moves that a fighter could draw on, but only when they successfully hit, and then by a margin....
Hit by less than 2 difference.... Basic attack
Hit by 2 .... A little bit of an opening to do a minor stunt ( eg at will)
Hit by 5 .... A more substantial opportunity to do a more powerful stunt ( per encounter or x/ day)
Hit by 10 ... An enemy is completely off balance or out of position, do you best stunt ( daily)
Certainly makes creating advantage a very important tactic, especially against more advanced foes.
.... For balance the same mechanic would have to have a similar mechanic for spell casting ( casting check)
... Just a throw away idea
I hope the Warlord never shows its face as it was in 4e. I do not want some non-caster healing anyone or somehow making you move faster simply by shouting.