I should answer my thoughts on these too: this is the way I think of these techniques, If I seem to criticise it's because 1. I care. and 2. I want an honest reaction if you disagree.
1. Bringing closed fist up to shoulder before doing a gedan uke (or gedan barai).
I used to do this in kata, but bunkai I felt open hand was more natural. since not many people punch and kick at the same time, I practice this block by only bringing the fist to about elbow height. there are other technique that effectively deal with punch/kick defense.
2. Head snap to first look in the direction you are going to move next.
yeah, I was taught to look first...but moving your eyes first then moving your head with your body makes more sense for less telegraph. if you notice...old footage of masters don't turn their heads first. I have a couple of theories as to why that is.
3. back leg is straightened in zenkutsu dachi.
only at the moment of impact!
4. open hand with thumb bent in.
I broke a thumb doing this once during a ridgehand strike...haven't bent my thumb during it since.
5. open hand with fingers straight and together.
yes, but I'm often loose with the hand until right before the moment of contact.
6. lift back heel slightly when punching.
blech...horrible loss of power. when you have your heel up it acts as a shock absorber...you don't want to absorb shock! you want to transmit it! have someone push your punch and notice the difference between the two ways...let me know what you find out.
7. full turn of fist to horizontal when punching.
3/4 turn...everybody knows that. some do 1/2 turn which also makes more sense than full turn.
8. guard hand is palm up during open hand strikes.
this is the way I first learned...later I was taught to keep it at a more comfortable and efficient 45.
9. crossing arms at midbody during blocks.
does anyone ever actually do those blocks in sparring? no, they don't. sure you could make up some elaborate and maybe effective bunkai for this, but when you really think about it...it doesn't make much sense to ever have both arms tied up at the same point in your center IF you are just blocking.
10. knifehand strikes starting at the head or from behind the head.
complete waste of travel distance unless you are breaking boards.
11. long and low zenkutsu dachi.
another blech...don't see this stance too much in full-contact sparring either. no manoverability. forces an overcommitment to the technique. and begs for a sweep/takedown. a stance for show only. they should rename the long-n-low to 'trophy stance'. I think Elvis popularized this stance.