Kaigangio, I will not let her rest, not yet.
Various legislation are still in force including the most recent one, The Act of Settlement (1701) that lays down that only Protestant heirs of Princess Sophia, granddaughter of James I, may succeed to the British throne.
The crown (the regal power, not necessarily that metal that sits on her head in portraits) means all to the Church of England, whose head is the reigning monarch now Elizabeth.
Doing away with the crown means doing away with the Church of England, founded by Henry VIII in 1534. There has since been updating of the relations between the Church of England and Rome. The Church of England has been absorbed hence there is no more need for Elizabeth and her lineage to maintain something they should not have in the first place, since 1215!
By the way, isnt it strange that these old agreements despite being extremely obnoxious through and through by current standards are still binding today?