I've always thought Drenthe should have played, you play your best team to win games, simple as that. Any other issues you deal with seperately and let's be honest none of us know what really happened or how bad it was compared to what other players have done/do. I think it was more about Moyes's ego and control freak mentality.
Footballers get paid a fortune but everyone seems to be worried about their poor delicate little state of mind if the naughty Drenthe had played, it's bollocks. I'm sure the whole squad would have felt happy enough if we'd won the semi final and got to the final.
Moyes got it wrong big time, Gueye was, as we all knew he would be, totally anonymous whereas Drenthe would have scared the shit out of the shite and given us the outlet we badly needed in the second half.