I bought this book a couple weeks ago, looked at the classes, looked at the feats, and very briefly skimmed the manuevers, said "meh" and put it back on the shelf. Then I read this thread and my interest is piqued... I guess I was missing something. Well, I go back and read the manuevers and holy crap, they're really awesome.
I love the manuevers, I love the way they've been implemented, and I think overall it would be a great addition to any campaign. Yes, even sword & sorcery campaigns. IF you think it's all throwing fireballs from your a la street fighter, you've obviously only read the first discipline - desert wind. From what I saw last night (I only read 4 or 5 of the disciplines, to be fair), it's by far the most supernatural out there. Divine Spirit is, but it's only available to a paladin-like class anyway. Iron Heart, Diamond Mind, and White Raven have barely anything that would be considered over the top at all (at least special effects wise).
As for power... it's really hard to tell. It's a brand new mechanic, and a lot of the really good effects are high level. Maybe it's ok, I don't know. I do know that the ones I was saying "wow" to were no the 100 damage 9th level manuevers. I was saying wow to a lot of the White Raven stuff - letting your whole party charge, get cumulative bonuses, and no attacks of opportunity? Awesome.
If this is a preview of 4th edition, I say, sign me up!
As for whether or not the warblade is overpowred... hard for me to say. I'm with the camp that the fighter is underpowered (though PHBII did help a lot there), so I don't mind if the warblade is a little higher powered (and I think it is). But I don't think it's crazy. Please people, don't call the difference between d10 and d12 major. Don't say he's "far more tough". It's 21 hitpoints at level 20, where that's often within a standard deviation of a single hit. 11 points at level 10.. yay.
I think it'll need to be played to see how it really works out. I think the loss of the bonus feats (Warblades get them, but from a very limited list, and almost none of them are straight "do better hitting" types) will hurt them a lot more than you think. They can't just automatically take weapon focus, weapon spec, etc, if they're taking feats for their maneuvers as well.
So... my guess is (since that's all any of us can do until we play) is that it'll be powerful, but also a hell of a lot of fun. And in my opinion, that's a lot of what the fighter classes needed - a strong injection of fun. How many times have you played with a pure fighter type and his turn consists of "I hit it. Done."? PHBII made melee fighters viable, TOB makes them fun.
-Nate