While I agree many people do think the monk is underpowered, I believe you have to be worried about overshadowing the actual Psychic Warrior. Since it has the same BAB, and worse saves, you would have to assure yourself that what remains of the Monk after you try to balance it is not obviously better than the combat feats that that class gets.
Some people think that the Psychic Warrior is overpowered, and I though I don't agree with them, I think you'd be hard pressed to say it was underpowered. So if your Psychic Monk is an obviously better alternative, you've probably gone too far in terms of the strength of the class.
Edit: Though removing the flurry ability might be going a bit far. Obviously it's a matter of taste, but I think most players see it as iconic of the class, even though it, at the beginning, is the equivalent of the Two-Weapon Fighting feat.