The only thing I can set my finger on now (after digesting this new build for a while) is that Psychic strike seems a little limited. Sure, you can add 4.5 points of extra damage per level (45 at level 10, 90 at level 20) to one of your attacks in a round, while a rouge does one third that (17.5 at level 10, 35 at level 20), which balances out since rouges get to add that to all their attacks under the right circumstances.
Only problem is rouges can sneak attack all day, while a soulknife is limited by his power points. A 3rd level soulknife can use psychic strike at full power once a day, at 7th level twice per day, at 11th level three times per day and to a maximum of six times per day at level 19 and above provided he doesn't manifest any powers that day.

I would suggest doing something to allow the soulknife to psychic strike more than once per two encounters while at the same time keeping its damage under control.
Maybe add psychic strike damage to an attack as a swift action (limiting it to once per round), low or no PP cost and using current number of die or a number of die equal to BAB.
That would keep Psychic strike under control while freeing up PP for manifesting combat critical powers.

Also, I would suggest upgrading the soulknifes manifester level to full, since many low-level powers need augmentation to remain useful at high levels. Limiting the Soulknife to fourth level powers at the most is enough of a manifestation limit I think.

Just some thoughts I have.