A curse upon the oath of allegiance?

In this article, Norman Baker: A curse upon the oath of allegiance | Comment is free | guardian.co.uk we are given the reasons why a parliamentary motion is being put forward to change the oath of allegiance an MP swears on taking their seat. Part of the argument is that it discriminates against republicans. What do you think? Here's the oath: "'I swear by Almighty God that I will be faithful and bear true allegiance to Her Majesty Queen Elizabeth, her heirs and successors, according to law. So help me God.'"
Now, that's the same as I, as an Anglican in England have to declare (yes, I use my right to declare not swear), on taking up any clerical post. I also happen to believe that we would be better a country as a republic. Do I square that circle? Yes; I don't see it as a circle to be squared. It's simple: the words say "... heirs and successors according to law..." Now if we peacefully and democratically and lawfully became a republic that would fit; the successors would be elected or appointed by a democratically approved process. In the meantime "true allegiance" means obeying the law and 'giving to caesar what is caesar's' (let the reader understand). I have no problem with that under present conditions. I'd prefer not to say it, but in the meantime, I can put up with it.