Dave pointed me toward a great blog called 3 Four 3 that I want to highlight, because I think these guys have very much the right idea when it comes to the qualities that make a player great:
This term "elite" is very often abused. In conversations with players, parents, fans, coaches – the soccer community in general – I have heard many label this or that player elite. And many times it actually is a decent player. But elite they are not! Also, it’s amazing how many times the player that was referenced is in reality just one of the bunch.
The issue arises because people, specifically in the US, have the wrong idea of what constitutes elite. Their metrics are just flat out wrong. The most resounding error is focusing on physical attributes. Is he big? Is he strong? Is he fast?
This does not make or break elite status!
What makes or breaks you are two and only two fundamental attributes: Technical Quality and Soccer IQ.
Please read the rest of the post and the blog as a whole, because these guys are showing a kind of thinking that is not found often enough in American soccer. The point that they make in the post referenced above can't be made forcefully enough. What the professional American player is lacking generally is not size, speed, or strength, it's some combination of those two attributes they identify. Think back on the Sounders season, and remember those stretches when it seemed like nobody could string more than four passes together. Remember the possessions that went for nothing because someone couldn't trap the ball or needed too many touches to control the ball. Think back to those times when we couldn't get past a team packed in their own end for ninety minutes. To use their terms, these are failures of technical quality and soccer IQ.
Of course, this is hardly a problem of just the professional level. American soccer suffers from this at all levels from the toddlers on up. I saw a particularly stark example a couple of years ago. A friend of mine, who coached his son's U-12 team, invited me to see them play in a local tournament. We arrived a little early and a girls' match was finishing up. We watched as we waited for the field to open up, and I saw a little girl anticipate and intercept a pass, smoothly dribble around the opponent she had just beaten to the ball, and take off down the field, head up, looking for her teammates. Impressed, I turned to my friend and said, "That number 44 is pretty good," to which he replied, "But she's so small." I really wish I could say I was surprised at his response, but unfortunately that sort of thinking is all too common.