Is it fair that Edward VIII had to abdicate to marry Wallis Simpson, while Charles can be a divorcee and marry a divorcee do the same thing without consequences? Of course, it was rumoured that Edward VIII had Nazi sympathies, so perhaps it was providential that he went before the Second World War, indeed there may have been more going on than we know.
It is not wise to get married if you have not broken off all ties with your former girlfriend. So Charles' divorce may have been only a matter of time. However now Charles is where he is (so to speak). For the couple personally of course it is better for them to get married.
There are of course many issues worth discussing. The big question of course is whether monarchy (rule of the one) in 2005 is morally wrong in an absolute sense. Going beyond that, there is also the problem that Charles's divorce should have barred him from being the next king if the 'rules' of the monarchy still apply at all. However perhaps they don't, some argue that the easiest thing would be to just call the whole thing a day when Her Majesty dies.
From the religious side of things, it could be argued that there is no King but God, and we should call no man King/Queen (see for example, Matthew 23) and to do so is idolatry. From a secular viewpoint, is it right that children grow up knowing that they have a place and have to stay in it?
Is the argument that it wouldn't be Britain without a monarchy is like saying Africa wouldn't be Africa without Malaria?