So who would have been? All a bit of a lottery.
The King of Bling (love it) had gone on the run and collapsed with bleeding feet and was hidden by very ordinary people he came to love and respect (and protect when restored) helped out enormously during the Great Fire of London and made the monarchy viable again. He didn't claim to be divinely appointed and didn't divorce his Queen (under some pressure) when she couldn't give him children. Quite remarkable.
There is no divine right. We are equal. I would rather have a head of state from the remarkable panoply of British history, for good or ill, than an anodyne person who offends noone, if such a person can indeed be found. Cromwell wasn't it. It is a bit of a lottery but one well under the control of the people now.
As Charles II said "I have no wish to go on my travels again". William will be the first monarch directly descended from him (2 lines) and I think will comport himself in the same way. With less bling, possibly.