Arsenal youngsters you had the most hope for but ended up flopping?

[Özim]

For me it was Aliadiere and Vela.

Aliadiere's career was ruined by too many injuries, Vela just never improved under Wenger.....under a different manager he may have blossomed.

With regards Pennant, when Wenger signed him he claimed he was one of England's biggest talent, but then he does have a tendency of overhyping stuff so you have to take his words with a large pinch of salt when it comes to his views about players. It's another reason he's a bit of a joke, the ridiculous statements he comes out with.