You're hit on the "shanks." I'm having the same issue! I'm in the midst of a 4th place standing with 6 wins and 5 draws. Manual shooting is making it really hard to be able to pull away in matches like I used to. But here's what I've found out about shooting in a nutshell. You have to use the LS to get yourself into postion for the shot and then after you press the shot button you've gotta also use the LS to aim it, too.
So a lot of times I just don't have the reflexes to get it aimied propeerly, especially in tight places. But it is football, right? I'm getting some realistic shot totals, I get about 5, 6 really great scoring opportunities a match and getting about 2-3 goals each. I've had about 6 1-0 affairs in about 35 games on manual.
I'm really just finding that it is even more important to work the ball around and use my dribble to break down the D and create openings to get good shots. I can still go route one, but I find myself shanking a lot of them at full speed, especially if I have to do any type of directioanl change as I'm trying to get an angle on goal. The LS shooting direction is player postion-relative. The other shotting modes seem to be based on the goals zones and everything automatically heads at the goal. In the Arena I've totally missed the goal wide by 10+ yards hitting the LS the wrong way. And I'm still trying to figure out how to shoot driving diagonally in. I'm always pushing it across the face of goal with no touch. But I'm not really very good with finesse shots.
That really isn't a comfortable button combo for me. I'm left handed so the more things I have to do with my right, thew worse it gets. I pretty much use the RS to do as much as I can.
Now I know that I was babbling about the RS with shooting before. There's still something to using it, but I don't know how it all comes together. I know the LS aims. But with passing and heading the RS definitely plays a part. The Nani to Gourcuff off the free kick was by my using the RS to head the ball into space and then a LB tap to a shot for the goal. Try adding the RS to your shooting. But I will say that I ended up contacting EA about all of my thoughts on how shooting worked, and I was wrong about how advanced it was. It seems to be the main mechanic is LS to dribble, shot, then LS to point it in the right direction. Not aim at a quadrant of goal. I'm still gonna ride manual till '10 drops. The quality of my goals is up 100%. The goals don't feel nearly as scripted now. I've seen more different goals in the last month than all of the other months combined! Brian