As I said in another thread, I saw Alphons Groenendijk's debut and that he would be amazing but it never happened. To be fair, as a youngster I thought pretty much every single player we ever bought was going to be amazing!! I was giddy over Kit Symons, Alan Kernghan, Lee Bradbury...you get the idea.
If Joey Barton had a decent bone in his body he could've played at a much higher level than he did with us. Obviously he is a grade a1 bell end, but I remember watching him and thinking he was a raw but complete midfielder in that he could tackle, run, shoot, take set pieces, pass and play box to box. He wasted his career and maybe if he had the attitude of a Silva/Zaba etc he would've gone on to a bigger club at the time and been an England regular.
Balotelli was another player that I thought has wasted his career. He was tall, strong, quick, great feet and absolutely ice cold. He would take a sudden death penalty in the world cup final the same as he would playing with his mates in the park. He had all the talent to become one of the best players in Europe, but again didn't have the attitude. As I've said before, my biggest worry with Balotelli is that Ferguson would've bought him and made him into the new Cantona. Balotelli had that something about him and on his day he was unplayable but when it wasn't his day he was useless - similar to Adebayor.
Last one was Anelka. That guy should've been world class all his career, but the fact he ended up playing for us at the time showed how much he'd fallen. On his day, no one could get near to him - fast, tricky, composed and could finish. All that talent at 18/19 but he basically blew the lot. If he had the right attitude - again, it's attitude - he would never have ended up with us and could've won plenty of Ballon D'ors and the rest. Don't get me wrong, he did well for us, but he had so much more to offer at the time.