Having that vision isn't a "tweak" to your game, it's how you grow up playing and usually have from a young age. Arsenal's tactics are built around Cesc's vision and passing range - Nasri simply doesn't have that. He's an attacking midfielder, not a centre-mid.
He's not played well on the left hand side. Not sure why, but whenever we've played him there, he's not been as good as he can be. Giggs has drive, but his main quality is his experience and passing range.
Well if we do sign and start few games as CM then surely he will adapt to that role isn't it. He doesn't have passing range of Scholes, but he can carry ball forward.