I'm frustrated and encouraged by the source material I find in my research. For instance, I have a book and DVD by Scott Rodell, and a book by Stuart Olsen. Both men were students of TT Liang, and both men are determined enough in their studies to have published multiple guides on Tai Chi Sword. Thing is, if you compare the descriptions of the 13 cuts in both book, many of the techniques are wildly different from eachother! It's possible that there's some subtle link between the techniques that I don't understand as a novice, but I think it's just more likely that there's little if any concensus on what the 13 cuts are and how they're used. Therefore I can march ahead with the (possibly naive) confidence that my interpretations are about as worthy as those that precede me.
Take Dai for instance. If you take it as simply a funny-shaped high parry, even if you combine it with Ge and Ya, you end up with a system that appears very limited in options. Even foil fencing, which is pretty simplified as martial arts go, has nine parries, semi-circular and circular variants of those parries, yielding and pressing variants, and transfers. That means there's explicitly much more than thirty expressions of defense without including footwork and voids.
If you take Dai as high left and high right, you find yourself in a strangely limited space. If you take Dai as the act of drawing out your opponent's blade, guiding it to fuller extension in order to maximize the space in which you can move as well as enlarging the areas you can attack, that presents a more reassuring and satisfying set of possibilities, doesn't it?