I was looking up the forum to read up about this class when I stumbled upon this thread. This is probably too late for you, but you could consider the psi warrior as some kind of "sword sage" who uses ancient mystical techniques.
That could work but it may be two sides to a similar coin. For my homebrew game/setting/system, I have the classes all broken down into categories: two that use/have magic and/or supernatural powers of some kind - the Mystics and Wizards; and two that do not use/have magic built into the class at all - the Warriors and the Rogues (there are still skills and "feat-background-trait-like" Themes that can give one of these classes some access to magic/supernatural powers).
The [base] Psychic and associated psychically (psionicly) powered permutations thereof fall under the "Wizard" classes: users of magic and/or supernatural powers inherent to them/their mastery and control. The Psychics, clearly, possess "mental" powers of some supernatural origin, not using sorcery or "spells," as such.
So, for my game, the Psychic [who knows how to do] Warrior [stuff] would fall under the umbrella of a Wizard class: Someone with access to supernatural mental powers, permitted some minor access to armor, limited weaponry, and martial training/talent for using those powers in combat.
The "sword sage"/kensai/master of the "way of the sword" kind of guy, to my mind, would fall under on the opposite side of that coin...under the aegis of a "Warrior" class. Someone whose expertise and "special-ness" comes from their combat ability, their completely amazing exacting use of their weapon of choice (most commonly, if not exclusively, a sword), and even maybe some philosophic or "mysticism connection" with their blade stuff that would feel/play like "chi powers" without being actual spells or magic...incredible, amazing, even unbelievable feats to any other kind of warrior...but nothing supernatural (like teleporting around the field of battle or turning your blade into a lightsabre), no magic.
All that longwindedness said, I DO like the sword-sage/kensai concept for a character class (beyond just, "I'm an expert swordsman" that any fighter or knight or any other warrior could bill their character as/put into the PC's narrative). I have toyed with setting up such a class to make/use.
The "psychic-powered" warrior, though, using their "magic/mutant powers" in combat is something else.
PS: And I am ALL FOR having different directions/avenues for players to pursue their character concepts. Not 'infinite" (which invariably leads to option paralysis), but "multiple/different." And having a "Psiloi" psychic powers warrior type AND a "Kensei" swordmaster meditative-sage type that can provide different pathways to a similar, while not exactly the same, character is nothing but a plus in my book/game. I could also see both kinds of characters belonging to the same "martial order/college/dojo/pseudo-religious organization/etc..." in my setting.