This is getting more and more similar to a street brawl
I'm happy to stay out of the fight, but I still feel the need to say something in defense of katatedori
- wrist grabs.
I also believe that they were originally important i budo, because they were intended to stop tori from drawing the sword - and of course they should not be regarded as solitary things. Wrists were grabbed, followed up with all kinds of things.
The wrist grab, I find, is an effective beginning for getting control of an opponent. It is easily followed up with breaking the other one's balance, or a pinning (not to mention all kinds of strikes). Also, a good wrist grab is not that very easy to get out of, for the unexperienced. Anyone who ever tried to do a technique on Tamura sensei will know this
I go back to my probability calculations: The skilled tori can start the defense with a wrist grab, quickly followed up by other stuff. If the uke (with or without a knife) is even more skilled - well, I don't have to spell it out.