Gee I reckon the gap is getting bigger between the elite and then good ones and then team player types.
I think that applies to the playmaking positions mostly. Players with great instinct and playmaking ability are rare at the moment. There are some with plenty of ability but lacking the innate ability to read the game quickly enough to take advantage of their skills. I'd even say that a third class exists who are athletically gifted with pace etc but often they've relied on that instead of developing their skills as much as the less gifted athletes.
Examples
Cronk- Not the most athletic nor a poor athlete, but reputedly worked hard on skills his whole career and had great instinct and game smarts. Won't break too many games open with running ability, but can get his team mates playing very well through smart ball distribution.
Cleary- All the skills are there but not showing the instinct to take advantage of them.
Johnson- Great athletically. But skills not as polished. Better with the ball in hand than at getting the best out of his team mates.
Seizer- developed skills and decent athlete. But not visibly great at reading the game.
When it comes to the forwards I think that it's mostly a question of bravery coupled with the size and physical prowess to dominate opponents. There's certainly a few that are specialists in creating second phase play, but you can be a star forward just by being a great battering ram. The skills development required and game reading ability aren't terribly important.