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About PvS, I only saw the cards and planned some strategies with them, But as long as I never played with or against post-PvS warlords, I really can't say much about them.
About bloodwave warlord being the worst mage, I don't argue with that. Yet I believe that the way to make him better is bringing him new cards and not errata. I really like the way arcane wonders make warlords a bit better with every expansion coming out, and not trying to make a big move that might turn them overpowered. That greatbow promo is also a sign that they try to close the gap between the warlords a little bit. About trying such errata as "House Rules" in your gaming group, they do sound interesting, but I hope arcane wonders wouldn't errata in the warlords' case.
Now about-
They give a better ability, with three choices, one of which is almost always worth something in most scenarios. They are worse, because they cost an action to use, and an always useful minor ability is rarely worth an action. Any Warlord that finds himself with spare actions and/or not enough mana for a 'proper' spell on anything like a routine basis should be playing Meditation Amulet - and many of them do. If you have 1 mana, and an amulet, you will almost always meditate over casting a Battle Order, so really they are only used for books that don't plan on this circumstance, but just occasionally end up in it once in a blue moon. I agree changing Battle Orders to a Ready marker 'free action' would then see them being used.
Meditating is a full action and commands are quick actions, how could you even compare between then?
While meditating warlords usually don't move too much, they often bring the Horn of Gothos and use quickcast to give all soldiers in the arena "Fast" or "Armor +1 and Tough -2" for the round, at least in turns that they bring big creatures/equipment from the Barracks/Battleforge (and turns they save mana to bring big things on the next round).
A non-meditating warlord often use his full action to attack or guard, so on the rounds he want to bring big things from spawnpoints (or the rounds he want to save mana to bring big things in the next round), a battle order might be the best option in many cases.
It is so rare that I spend my full action casting a quick spell while staying in the same zone outside the first 2 rounds and not under the effect of enfeeble, that I just don't understand what made you compare casting battle orders to meditating (almost every time I use my full action to cast a quick spell, I also move my mage as part of that full action).