It's neither "speed," nor "IQ," nor "skill" which makes a player great, much less a team. It's a suite of talents which make a player talented, and a diversity of talents which make a team great.
I coach girls on the small-side fields, which means the youngest ages. All these teams are built from scratch, starting with zero players. Which compels me to spend most of my weekends scouting for talent and recruiting players. Having zero players to start with is always a challenge, but at least it allows me the freedom to choose what type of player to look for.
One thing learned over the years is that great players come in all shapes and sizes. Diversity of skills on a team are highly important. So, rather than choose just for "speed" or "IQ," I look at a continuum of 4 factors, in descending importance:
- dominance on the field;
- aggressiveness;
- speed; and
- skill
Dominance on the field is the most important factor. A player who is always finding the ball usually has something which makes her great. It might be IQ, or skills, or aggressiveness, or it might be speed. Whatever it is, it makes that player special.
Aggressiveness follows in importance. Kids who crave the ball and get to the ball first are like gold. You might need to teach them how to play intelligently. But each of those kids might give your team an extra 5-10 possessions during a game.
You cannot have "slow" kids on the field if you want a competitive team. Median speed is fine for most players, but kids who really are "slow" have no business playing on a club-level team. They cannot get to the ball unless somebody serves it to them. They win few 50-50 balls because they are always a step behind. I don't care about a kid's "soccer IQ;" if she can't get to the ball then she can't do a lot to contribute.
Skill is the least important factor to me at these ages. I find it very easy to teach kids how to handle a ball and play a possession-style game. We probably do about 20,000 passing repetitions per player per year in practice, as well as Coerver-style drilling, and we have live scrimmages at nearly every practice. On top of that, our teams play in about 50 games and scrimmages per year. So the skill develops pretty quickly.
Conclusion: There is no single factor when selecting players. But there are factors that indicate that a player is a "no-go" for recruitment. The most common for me is when a kid is slow.