I think it is a blow for England mainly because right midfield options are few and far between right now Lennon would have been the obvious choice but he is a doubt for the world cup as well, Joe Cole could go there but how much football has he had since his injury? There could be Walcott he brings pace but if we are being honest thats pretty much all he bring at the moment, Wright Phillips blows hot and cold and you need a stable performer in the WC and that's pretty much all Capello has to work with.
At the very least Beckham would have brought experience, vision that none of the aforementioned have and leadership something that we know England will need in South Africa I think Beckham would have made it and he would have played because prior to the injury he was better than the other options because they are either inconsistent, one dimensional ( for the most part) or not playing regularly I know people will say oh he only crosses well or takes free kicks well it's those things that can help you win games and I do think there is more to him I think his passing is better than most I think he has good vision with through balls etc and I think he is a leader with or without the armband, Capello would have taken him he has pretty much admitted that and in a World cup you take the players that are best equipped to do you a turn and Beckham is one of those players