Iniesta is a more complete player. He might even go on to be a better player than Xavi, as imo he has more in his locker. But for the time being Xavi is the better player, and for you to call him average, even in contrast to this talented Barca side, is way too far fetched Seven.
Xavi is the second best midfielder in the world this year, and he has been instrumental to Barca's success. He doesn't always pass sideways, he is Barcelona's most creative player FFS. He does pass the ball sideways more than he should though, but thats only because Barca's gameplan is to always play possession football, so Xavi ends up only taking calculated risks.
Bottom line is, he's a brilliant player and today he was, along with Iniesta the best player in the game.