Soulknives can't get more than a +5/+4 Mindblade (and it has to have the +5 on attack, you can't mix and match it at all).
Soulnkives are also very item-dependent. VoP hurts them.
Never played a soulknife, how are they item dependent? I thought the whole point of them was that they had a weapon that could never be removed.
1: The weapon is only a +9, and can't be optimized due to lack of options.
2: The removal of the weapon opens up more of the WBL, which allows you to attempt to make up for the 3/4s BAB, mediocre Sneak Attack variant, and poor skill selection (they have a few decent ones, but the rest are crap).
3: They desperately need a better BAB to be a front line class (which their Hit Dice and Armor Profs suggest they should be, but they aren't).
4: They are billed as a stealthy class, but lack the skill points and abilities needed to be a skill monkey.
5: Their analogue to Sneak Attack, Psychic Strike, is a joke. It takes a move action to use, and is a mind-affecting ability (and only works on one attack). They would be better off with Greater Psionic Weapon, and that deals
less damage!
6: Their class abilities are so divided on what they think they should be doing (Whirldwind Attack, ranged combat, TWFing, THFing) that they can't focus in on a single option without the others being wasted, and their ability to cover those options is vastly inferior to the Fighter or Barbarian or the Ranger.
7: Ranged combat is impractical for them unless you have Complete Psionic, which opens up a whole 'nother can of worms for the rest of the Psionic classes.
8: TWFing with the Mind Blade is so impractical that you should never resort to it.
In short, they need to spend more money to cover the above weaknesses. The lack of needing a weapon is nice, but it just doesn't cut it (pun not intended).