I'm not your coach, or there to see it in person. But from the video alone, I can tell you that much of your problems are simply because your stance isn't wide enough. Your feet are too close together, meaning you are too upright and having to bend too much. That is affecting your technique, balance, and ability to make saves on the ice and down movements. Simply, you are too high off the ice. Get your feet wider and bend your knees more (just doing one or the other won't help). Keep your knees closer together under your body, not as wide as your feet. If you keep your knees more in a straight line, you'll be leaving your 5 hole exposed, and not be as agile, just like your coach said. As far as the 5 hole, my pads won't cover mine fully either. You have to focus on bringing your knees together, not your feet. Even if the thigh rises don't touch, having your knees together and your stick in place will close up that space. If there is a little tightness in your hips when you go down with your knees together, bring your butt down a little, that should do help. Also, if you go to Sarah at PAW, she can make you a thicker landing block. The increased height, even 1/2", will help alleviate stress on your hips when your knees are together because it allows your ankles to drop lower than your knees. I know it's difficult to get your feet flared out. I have a narrow butterfly also. I'm not talking about widening your butterfly, it is what it is. But if you worked on dropping by bringing your knees together, even if your feet go back, you'll see improvements to your mobility and speed . You can't keep your butt up if you bring your feet backwards. You'd fall forward onto your face. They are linked with each other. I have an older goalie that I coach sometimes. He is used to playing the old stand up way, and had a very difficult time learning the new techniques. His stance was too upright, and his feet too close together. When he dropped, it was like you, his knees went forward and his feet back, and he would get stuck like that and become unable to make second saves or move around the ice. He also had hip mobility issues like you. We were able to get around them by loosening up his pads a lot, especially his toe ties and boot straps. And getting him to widen his stance so he can bring his knees together, but while still being able to drop his but lower to take the stress off his hips. Now he can drop into a regular butterfly, and move around the ice better. He needs to work on his weight transfers and such to really be able to slide around. But he's become pretty solid. His hands, stick, and angles were pretty good before. Now that he is getting wider and lower, he's become pretty solid because his pads are much quicker, combined with the rest of his game. I think you'd see these kinds of improvements also.