bungalo, most times I agree with you, but Yassis does make some good points from the novice standpoint. Whether or not he is who he claims to be doesn't matter, a lot of his sayings are dead on.
On open stance: yes, its very hard to generate depth and power from an open stance 1hbh. I know I have problems with it, and would much rather just take the extra step across the body and hit it "ultra closed" instead, so I can get more shoulder turn. Agree with you here.
Technical/"Old Skool" coaching: agree with you here, as well. It is necessary to have some form of foundation, HOWEVER, it is quite possible for people to literally pick up a racquet, swing it a few times, and get the hang on tennis. I have seen it in person several times. A player who has been taking lessons from my same coach for around 3 months has been beaten 3 & 0 by a person who had never even watched tennis before. This has happened on several occasions, and isnt nearly as rare as you claim it to be. BUT, that same player who is so natural DOES require formal technical training, at least guidelines, in order to get the most out of their shots.
On/behind the line: I personally play on the line, and the information yassis gives regarding deep balls is spot on, which makes me have some sort of respect for his information. It is very very difficult to make a neutralizing half volley if the player puts balls on the line. This is when you MUST back up, or you are 1) not able to create your own power and 2) not playing your game, since you are just half volleying. Playing on the line is my preffered way of playing since it allows you to get the ball early as well as transfer your forward weight into the ball when physics dictates it will have the optimal return force.
On people's over-technical postings: It annoys me quite a bit to read the micro-technical details people are worrying over. This is my strongest agreement with Yassis. It is not necessary to focus that much on rudimentary technique. Technique is as much learned as it is taught. Before you get your breeches in a twist over this statement, let me say this: no student automatically does everything perfect immediately after you tell them what to do. If this were the case, coaches at bolleteri etc would be churning out Federers by the hundreds.
Swing speeds HAVE increased since the days of wood racquets, do a search on serve/forehand/backhand RPMs before and after graphite and metal racquets hit the scene. A racquet alone does NOT generate more rps, if the two in comparasin have comparable string patterns.
Yassis' swinging from the tip standpoint is a bit risque, it makes for a very wristy (and uncontrolled) shot. You would be slapping the ball instead of hitting it, if you were even slightly off here.
Accelleration and racquet head speed does transfer to more control, since spin = control because it allows for a greater margin of error. So, racquet head speeds have a profound now, but they always have, as BB said.
Loose grips are important, i dont know how many times i've missed volleys/backhands due to "stone hands".
Reverse forehand: I've actually never heard that term anywhere but this board. I hear it more as the "inside-out" forehand/backhand. It makes more sense. Reverse forehand would be a backhand, and vice-versa.
"Many of the people (club level professionals) who analyze the game have never played at a high level themselves."
So true, I can give you about 100 high school "coaches" who analyze the game but suck to no belief.
"Winning is something you can't teach."
Again true, but as BB said, you can give players the TOOLs to win, but that doesn't necessarily mean that they will win every match just because they are technically more sound. This is why everyone gets so pissed off when they play pushers, who dont have a care in the world regarding weight transfer/form/spin amounts; they get the ball in play any way they can. Technique loses to match experience, pretty much in every case.
"You always have to prove yourself and the only way to get better at winning is to play a lot of matches. "
I have said this myself about 50 times, at least. Playing matches is the only way to improve after you learn the strokes. Match mentality is what seperates top 10's from top 100's. They all possess the strokes and can hit 1000 balls in a row without any problem, it is how they use them that makes the difference.
BB, seriously man, just because he disagrees with some of your stuff doesn't mean he's saying "IN YOUR FIZACE I PIZOWWNED YOU, OLD TIMER!", there isn't really a cut-and-dry way to play the game, anymore.