Ok, ready? Since her blog post actually skips #1 on the list and goes right to #2, let's follow suit.
#2) The point made: the saddle should not distribute the rider's weight evenly over the horse's back; that makes a rider harder for the horse to carry.
This is about finding a happy medium: you can't impinge on the shoulders, nor can you have the saddle sticking out past T18. The rider should be over the horse's center of gravity, and in my world, the rider's weight should be spread evenly over a bearing area sufficiently large to prevent great concentration of pressure in one spot. I usually see people putting the saddle WAY too far forward - they're actually saddling the withers rather than the back, and invariably the saddle winds up inhibiting shoulder movement, either by getting the tree points in the way of the rear of the scapula or by jamming the girth in tight behind the horse's elbows. Also, keep in mind that the horse carries more weight on the forequarters than on the hindquarters, and in dressage (in particular), we're trying to get the horse to engage the hindquarters and lighten the forehand ... which is even harder to accomplish if the rider is too far forward.
#3) The point made: Longer, broader panels make your horse uncomfortable and put pressure too close to the loin.
Obviously, if the panels extend past T18, or are too broad or the wrong shape for the horse's back, you can get a lot of pressure, or pressure in the wrong place ... and there are saddles out there that do have a huge amount of panel in the rear. For a longer-backed horse (or a petite rider on a shorter-backed horse), this isn't a problem, but some saddles with "pointy" rear panels can create issues on short-backed or croup-high horses. I don't believe that longer, broader panels cause pressure at the rear if the saddle fits properly. Again, it comes back to striking a happy meduim. Panel size does come into play, it's true, but remember that if the panel shape isn't right for the particular horse - too angled or flat, or too deep/not deep enough in the front - you'll have trouble. And if your panels are too small, the rider's weight will be concentrated over a very small area, and that's going to cause soreness, too.
#4) The point made: short girths are unstable, restrict the shoulders and forelegs, and make the saddle sit too far back.
I've never noticed a difference in stability or an effect on saddle position or the horse's performance if the short girth is sized properly. If it's too long, it will catch in the saddle pad or flap; if it's too short, it will come in contact with the horse's elbows. I've also never noticed that short girths tend to allow the saddle to sit too far back - that's usually a function of incorrect saddle fit.
#5) The point made: Engaging your pelvis shouldn't make your "back pockets" come into contact with the cantle.
The cantle should not interfere when the pelvis is engaged - again, true. If it does, there's an issue with either saddle fit for the horse (saddle is sitting pommel-high for some reason) or fit for the rider (too small a seat, too wide a twist, or stirrup bars positioned too far forward). Contrary to what Ms. Haddad puts forth, this phenomenon is NOT limited to deep-seated saddles with big blocks and large panels.
#6 and #7) The point made: the old ear-shoulder-hip-heel alignment is wrong for dressage; it creates a "three point" seat.
While this isn't strictly a saddle fitting issue, it does make the former instructor in me prick up her ears. All I have to say is this:
#8) and #9) The point made: The rider's knee should never be behind the horse's center of gravity, and must be bent to act as a shock absorber. Being restricted and locked into the "supersize" saddle creates a stiff rider.
Again, totally agree ... and if the saddle fits the rider, the knee won't be torqued back. I'm not a fan of big blocks and deep seats by any stretch - I'll even go out on a limb and say that a rider who thinks they require those accoutrements to ride well needs to spend some serious time riding on the longe line without reins or stirrups - but again, if the saddle fits the horse and rider, this won't be an issue. Blaming big blocks and deep seats for this is a bit like blaming 4 wheel drive for auto accidents in bad weather - it's not inherently the thing that causes the issue, but rather the way the thing is used. The scalpel in the hands of the surgeon vs. the scalpel in the hands of the madman.
There's another rebuttal to Ms. Haddad's post, A Saddle Fitter's Perspective, written by Colleen Meyer of Advanced Saddle Fit. Again, I don't agree with everything she's saying, but we do share many opinions, and it's a good read. Enjoy!