I noticed in the text of this Martial Feat that you mention it as a fundamental fo Japanese fencing. I wanted to point out that there is a fairly similar fundamental move in European, or at least Italian, fencing as well, Guardia Prima. That literally just means First Guard, but Salvatore Fabris talks about it as follows: "Prima is that position which the hand takes in drawing the sword from the scabbard, when the point is turned towards the adversary - all guards especially with the sword alone must be formed with the point so directed." Of course that is from the early 17th century so all guards being point forward applies mainly to the use of the Rapier or other primarily thrusting weapons, but the primary point I wanted to make remains, that in drawing the sword a defense is offered, especially against a thrust.
There is also an offensive follow-up, with an immediate thrust, but it is more of a riposte, rather than a single cut, like the Japanese strike with the sword from the scabbard. Of course rapierists would more likely start farther away from each other to begin with, so...
At any rate, maybe there could be some kind of Guardia Prima feat that could be used with virtually any weapon cross-drawn from a sheath (well, maybe anything longer than a dagger.) So maybe this one would only give the +2 Active Defense bonus, but that would expand the list of weapons it could be used with to include other long-bladed weapons besides just primary slashers.
Admittedly the follow-up thrust to that could be a fairly quick movement from the first guard, but not as quick as the Nikutsuke move, I wouldn't think, so maybe an advanced form would allow something similar to the Nikutsuke advantages with straight swords? Or maybe only as a secondary attack, but with a wider range of weapons than allowed by the Nikutsuke form?