I'm playing a soulknife right now, but I'm higher level than the OP gave as an option.
I find that the move action to "recharge" (I have Psionic Meditation) is no problem, since the BAB only allows a single attack per round anyway. When I gain another level, my BAB goes to +6 and I'll have choices to make.
I use Psychokinetic as the mindblade enhancement (doing the math shows that Keen on my bastard sword mindblade results in the same average damage as Psychokinetic, so I may as well do the damage every round instead of at random).
I use Psychic Strike all the time since it provides +2d8 at my level and it doesn't require focus to be expended. And because it's not "precision damage" (like sneak attack) it will even work against creatures who are immune to critical hits (but as psychic damage, the target must be a living, non-mindless creature).
I don't see why this wouldn't work, but I haven't asked my DM yet: because I have Free Draw, I can create the mindblade as a free action; I could start to shake hands or clap someone on the back and instantly create the mindblade
after my hand is grasping theirs or is on their shoulder!
I haven't looked at Deep Impact, but I will have to check it out. I don't like expending psionic focus, though, since I like the extra 10 feet of speed provided by the Speed of Thought bonus feat.
Oh, and taking a lot of ranks in Autohypnosis has been great for me! I use the "memorize" and "willpower" aspects on a pretty regular basis. And I'd think the first would be very useful for an assassin...