What is technique?
A batsman's technique is the way they choose to play. It is how they get into position to play certain deliveries.
Now, the 'ideal' technique is supposed the be the most efficient when it comes to getting into position to play any delivery.
But each batsman has his own technique, and if it suits them, then great. The 'ideal' technique is supposed to make it possible to score of every delivery once mastered, and Tendulkar, Dravid, Ponting, Hussey, Bell, these guys are examples of players with this perfect 'technique'.
But many players have their own techniques. The only difference I see is that with an unusual technique, they make scoring of certain deliveries a lot easier (For Dhoni, anything pitched up or in his legs, Sehwag anything outside off) but make it difficult ot score off others (in the ribcage for these two). This is what differenciates a good batsman from a bad one, a good one can score anywhere. But these guys have worked hard and put in the effort, so that against the deliveries they are weak, they just get out of the way or get a single, and once they get one in their zone, they make it count.
So yea, technique isn't that important. It is about knowing your technique and how to use it, like aussie said. If I take my example, I'm one of the better bats when I play tennis ball, cause I slog anything on the stumps or anything short to leg, and deliveries I can't slog I push away for singles. I've got a horrible technique, but still score of nearly every ball.
Good tech can help make things easier, but aren't needed...