He got many chances and simply wasn't good enough. Silvestre Varela, for example, is twice the player Vieirinha is.
Also, no, he has absolutely no chance of making the World Cup squad. That's ridiculous.
imho i think hes a bit like varela in that he wasnt mature enough for the club he was raised in(sporting) when when moved to a new enviroment and given a vote of confidence excelled.
Veirinha is the same, pretty changed player these days, the main player of paok who prob will be champions.
Still the way he was playinh with porto, they did the right thing and got some profit from him..hard to say which players can end up becoming quality and those that wont when theyre so young.
Also the tournament you were talking about conceicao was the u17's which portugal won, and vieirinha was voted player of the tournament ahead of cesc fabregas.
He gained a shit load of wieght though in his late teens, check out a picture of them when he was 19/20...
paok really worked him into shape, and its paying dividents..alot of natural talent there to work with.