I agree with regards to predicting whether the ball would have gone on to hit the stumps as this is based on a model that predicts what would have happened had the batter's leg not got in the way. There's clearly going to be an element of error here as it's just a prediction. A very accurate one as testing has demonstrated but as with any measurement there'll be error involved.

But as for whether it pitched in line the technology is simply a camera used to replay what actually happened.

Ominous signs from Australia on day 2 but given they're still over 150 runs behind and with evidence in the series that they are perfectly capable of collapsing themselves I don't think there's any need to get too dispondent.

You’re still relying upon the accuracy of the camera, which assumes it is in exactly the right place.

To be honest I actually preferred cricket when the umpire just made a decision then the next ball was bowled what DRS has proved is that umpires are quite good Hartlepools finest is currently doing South Africa v India!

When DRS was introduced it was to correct real 'howlers' but now decisions are examined in the greatest detail which was not the original purpose.
Umpires' decisions should not be overturned for the sake of say, the ball pitching a millimeter off line, which happens these days.