Battlemind. Not the most exciting of names, but coming up with iconic and simple ones for something like a Psionic Defender can't be an easy task. You shouldn't take this as a signal that the game developers are running out of ideas, though, because this class' mechanics and power selection are among the most imaginative that the game has to offer. Let's take a look at them.
This is not a generic fighter with a brilliant halo painted over her head. Honest.
Gear-wise, the Battlemind is a defender of the old school: a reliable set of heavy armor, a solid chunk of metal to bash enemies with, and possibly a shield. On a battlefield, you wouldn't be able to tell them apart from regular Fighters, if not for the silly Halos around their heads. According to their flavor, they have egos that occupy several squares, and their combat style overwhelms opponents with sheer prepotence (which is somehow tied to their Constitution modifier). One might question whether their fighting prowess really justifies this degree of self-confidence, but there is one thing you can't deny: they have some really cool tricks up their sleeve.
As all other Psionic classes (except for monks, who aren't really psionic, but we love them anyway!), battleminds use a groundbreaking resource system for their powers. You can find a detailed description in my Psion review but, in short, instead of at-wills and encounter powers they have at-wills that can be augmented (in two different ways) by expending Power Points... which, appropiately, are regenerated each encounter. Dailies and Utilities remain unaffected.
So far, we had seen a basic use of power points in the Psion class, and a terrible one with the Ardent. Battleminds get to be the creative powerpointers. Baseline effects that would have looked completely out of place in non-psionic at-wills (like non-standard actions), lesser augmentations that are actually worth using, and even augmentable class features make sure that Battleminds are not just "like that other class, but with power points". Unlike ardents.
I am torn between loving and hating the class features. On the one hand, they are flavorful, slightly weird, and just different from those of other classes. On the other... they don't quite work as they should. While I'm writing this, D&D message boards all over the world are raging about the class' alleged incompetence at the Defender role. As usual, there is a good deal of exageration here but, as much as I want to like the class, even I have to admit that it feels weak on certain areas.
Their method of marking is actually pretty good, with an at-will power that lets them mark a creature within 3 squares for the rest of the encounter - or until you mark a different one. There is an option to spend one power point to make this affect two foes at once - something you won't want to do very often, but that could be extremely handy in certain encounters. In addition, there is a good amount of at-will powers that can mark enemies (sometimes in multiples!). Overall, they have multimarking capabilities almost as good as a warden's, as well as a Swordmage's ability to maintain marks at range. This would make them good candidates for Swordmage-like mark-and-run strategies... if not for their punishing mechanic.
The punishing mechanic, it must be said, is one of the coolest things that I've seen on a player's handbook. A power called Mind Spike triggers against enemies breaking a mark, hurting them for as much damage as they have dealt an ally. It's concentrated karma punching the monster on its face.
Unfortunately, its efficiency leaves a bit to be desired. It only works against adjacent enemies, it won't trigger on missed attacks, and it costs an immediate action. It is true that it never misses and that, looking at average monster damage values, it hits slighly harder than a maxed out Divine Challenge (by a few points)... but the basic attacks of other defenders will easily outdamage it.
Along with Fighters, Battleminds are the only defenders who can penalize enemies for shifting around them. But the similarities end here - if Fighters answer shifts with a swing of their blade (which is their universal answer to all problems), Battleminds prefer to do as their foes, and shift after them. Except that it isn't exactly 'after'. The power in question, Blurred Step, costs an Opportunity Action, thus resolving before the enemy gets a chance to get away.
While this is a good thing when attacking, in this case it prevents the battlemind from going into the square their foe is going to leave. Among other complications, this means that shifting enemies in a diagonal square from a Battlemind are gone for good - there is no way to end up adjacent to them. Also, a much-criticized side-effect of the Opportunity Action cost is that you'll never get an Opportunity Attack if the enemy then chooses to charge. Then again, that OA would have been equally impossible without Blurred Step, and at least there is a chance of moving to an advantageous position.
The build-related feature for the Charisma build ("Quick Battlemind") is quite original, as well as extremely useful for a defender. It grants them a free movement when the combat starts, giving an unprecedented control of where the front line will be set. I have lost count of the number of times that my fighter rolled a low initiative, only to see allies and monsters maneuver into hardly defendable positions - incidentally, this is part of the reason why I value powers like come and Get it so highly. At any rate, I see this as a major incentive to take the class.
As for the Wisdom Build, Resilient Battlemind, it honors its name with a power called Battle Resilience, which triggers the first time they are attacked, granting a high resistance to damage for a turn. This has the potential to go wasted if, for example, the triggering attack misses and nobody else attacks the character during that turn, but if you can somehow attract the attention of several enemies from the beginning, you can prevent a lot of damage.
Overall, the class suffers from a punishing mechanic that is difficult to use, so the plain mark penalty will often be the only adverse effect that marked enemies take. This is aggravated by the lack of good basic attacks, which makes the Melee Training feat a must.
Although the features left a bittersweet taste, a Battlemind's catalogue of powers is nothing but pure sugar. There is, inevitably, some filler material, but most choices are interesting either in their at-will or their augmented form, which creates a nice tension. More importantly, there are several at-wills that are radically different from those of any other class - great examples of the potential of the Power Point mechanic.
The basic lineup of level 1 at-wills isn't all that impressive, but covers essential functions. There are at-wills to mark, push, and penalize attacks, and augmentations for close bursts, blasts, and even a blinding debuff, all of them very tempting as spammable encounter powers. But the undeniable star is Iron Fist, a strike that grants resistance equal to Wisdom modifier whether you hit or miss. This looks like a better version of the Temporaty HP- granting powers of other defenders - which is to say a lot.
The real surprises begin at level 7. Lightning Rush is an Immediate Interrupt at-will attack! It triggers when a nearby enemy attacks an ally, allowing you to move adjacent and attack, sacrificing the standard action of your next turn (a necessary, but profitable tradeoff). If that wasn't enough, both augmentations offer great effects.
Also at level 7, and competing for the same slot, is Psionic Speed, which could be described as a marking, better version of Dual Strike that hits three enemies and can be used with two-handed weapons. This will typically be similar in effect to a Sword Burst, but it can easily be upgraded to a close burst 2 with a reach weapon. Also, the mass-marking should prove invaluable.
Even more gems await at level 13. Brutal Barrage is the first at-will (and probably the last) in the game that lets you attack a single target three times, incidentally knocking him prone if two or more hit. Of course, in order to keep the damage at a sane level, each hit only deals your Constitution modifier in damage - which, multiplied by three, is acceptable but far from stellar. Accuracy is nothing short of insane, though, and I personally find the interaction with Hammer Rhythm hilarious.
The next remarkable power is Armor of Blades (level 23), a variant of Lightning Rush that trades out-of-turn movement (along with its great reach) for the awesome effect of redirecting enemy attacks to oneself. It isn't probably worth taking over Lightning Rush, but I would be very tempted to take both.
Finally, Brilliant Recovery is another unprecedented at-will effect, though one that I see as horribly unbalanced. It is a minor action attack that you can only use after missing. It would be extremely effective, but actually fair, if it was somehow limited to one attack per turn, but it isn't. As it is, there is a huge incentive to force a miss on your first attack (say, attacking bare-handed with your eyes closed) in order to blow two minor actions for an improved Twin Strike. This really deserves errata, but once it gets it, it will be one of my favourite powers.
The selection of dailies is merely passable, in my opinion. For each level, there is an attack that comes with a stance that boosts opportunity attacks. Some of these are quite good, others less so. Nevertheless, I'm not sure it is a mechanic that justifies so many slots, as it gets boring quick. Utility powers are also decent, my favourites being an at-will Water Walk at level 2, and an encounter power that lets you turn a melee strike into a ranged 10 attack.