def wasn't referring to a specific coach. just commenting on general state of 1hbh instructions, one of the reasons why so many juniors don't see continued improvement in their 1hbh while all other parts improve.
some comments on the set of instruction. in followthru the guy in the photo def has his wrist higher up than the eye level unlike the teaching points, which I tend to agree with. this sounds like a small point but the swing path changes depending on such small finishing position. the ideal swing path needs to be more flat than too much low to high like in FH. the guy in photo swings very low to high. another point about elbow. agree that it should be straight at the contact but straightening too early is not a very good habit that limits the versatility of the stroke. the swing should be versatile enough to allow quicker swing than normal full swing without sacrificing the solidity of the racquet in position for handling high paced shots. bent elbow up high as a quick prep allows such kind of flat hitting. gasquet's prep is close to what i mean. also almagro.
in general i think low to high swing is too emphasized. coaches should understand wrist movement and range of motions are different b/w fh and bh.