I just think you should leave them alone. By accident of birth they have ended up where most of us would absolutely hate to be and yet you think that William should be forced to live in London with a young family, doing royal duties for decades before he needs to, and Harry should be stuck in the army because he chose it at 18yrs.
If William wants to escape to Norfolk, a much better place for a young family, using his training and expertise to do a worthwhile jobs then good luck to him! He can prepare while he works- it will be a very different monarchy.
Likewise Harry has given the army 10 yrs- wants to leave at the age most of his contemporiries are leaving and is using his skills for worthwhile causes. I expect that charities are keen to recruit ex forces people with the right skills of being able to organise, motivate etc. He may be high profile, he would be high profile whatever he did, but I image that is all to the advantage of the charity. The problem appears to lie in the fact that you don't think that working for a charity is a 'proper' job- rather that he is is going to drop in once in a while and not do any 'real' work.
I am not really bothered- I just think it is unfair to be so critical when they are being useful instead of just 'preparing'.