I'm certainly not intending to criticise Her Majesty's sense of duty. For my part, I think she should abdicate and enjoy her retirement, but then again, it's clear that she doesn't want to do that -- and, I think, even if she were persuaded to step down, I'm not sure she'd "enjoy her retirement" anyway, as long she had this sense of not fulfilling her oath.
I don't share ymb's concerns about Prince Charles becoming King, though. He seems to have mellowed somewhat, and is popular again, perhaps because finally his marriage with Camilla has been accepted. In any case, even if it were true, and Elizabeth II "fears for the monarchy", then a delay of a few years is hardly going to save it.