I don't think anyone is saying that William should sit and his rump and do nothing, at least I have not interperted anyone in favor of that.
IMO I would not say he has done nothing, he has graduated from college, (hardly nothing), he went into the army and graduated from Sandhurst. Anyone that knows anything about any military training would hardly say this is doing nothing.
William and Harry organized the whole tribute to his mother which we all enjoyed just a few months ago, and raised a lot of money to support his mother's chairities Diana, Princess of Wales Memoria Fund, National Aids Trust, and Centerpoint, of which he took over patronage from his mother (forgive me if I forgot any) I would guess these charities are not complaining that William did nothing for them. These are just a few examples, I am sure people can add other useful things he had done in his young life.
Next month I believe he will go on duty with the Royal Airforce, then the Royal Navy, following the footsteps of his father. That seemed to be okay for Prince Charles.
My point is, that he has done more than most 25 year olds in the US at this point in his life, so heaven forbid if he have a steady girlfriend and goes out to parties. I see that as nothing but normal for a 25 year old.
I think people should just lighten up on him. He seems to have a very good head on his shoulders and will do just fine. I am all for letting him be young while he morphs into his role. Where is the fire? Let him take his time.
JMO