I think we had a "what changes would you make" thread a while back didn't we?
IIRC it was unanimously agreed that the PP should have been 250PS (or more). I know VW would argue that their 230PS is better than the 250/260/270PS of rival cars because they can actually deliver that power to the road, plus the power band and torque aren't apparent from just quoting the max output... but still, I think it would divert much of the critisim of the GTI if it was a bit more powerful.
That said, I think most people who criticise this car do so not for any logical reason. They are often wannabes who can't afford one, or they bought an ST or Megan a year ago and want to pretend its still better than a new GTI. In that case its just easy to say "oh it is underpowered". If you take that away they'll probably just pick on the price next, "oh you can get waay better stuff for less money."