As others have said, it is a good thing he is dead, but I seriously doubt he has been running things for many years. The report I read on the BBC website says the compound they tracked him down to had no phone or Internet connection - kind of essential to run a global terror network wouldn't you think?
On the Obama/RW front: size of his secret service detail would have taken up half the Abbey! They would have wanted police background checks on all the guests to make sure there was no threat to him, etc. It would have taken the focus of the mist important people on the day - the bride and groom.
He may have been invited, but as it was not a State Occasion there was no precedent to do so.