Playing as an attacking midfielder makes him open to this feeling of "mecurial talent" one week and "overated kid" the next,
In that position where you are constantly running at defenders and trying to, and expected to, create chances one week everything will run for for you and you can have a hand in 3/4 goals and the next the ball just wont break for your or your striker wont finish their chances.
For every Gareth Bale that breaks through and then kicks on to consistent world class level there more than a handful of Bellamys, Townsends, Youngs, Downings, Adam Johnsons that break through and have a good couple of months and then fail to do it consistantly.
The jurys out on whether Sterling can break into the Bale/Di Maria/Ronaldo bracket but having 65 Liverpool matches and 9 England games under your belt still at only 19 is a ruddy good start!!