In theory I dislike the idea of a hereditary head of state. Why should someone, due to an accident of birth be given a life of wealth and privilege at the tax payers' expense? But the minute I think about the alternatives, I start to think the Queen isn't too bad after all.
A country does need a head of state and it's nice to have an apolitical one. Otherwise they will be disapproved of by all the people who didn't vote for them and might alienate countries they visit. Or at least alienate a large part of their population. You only have to see how divisive Trump is in his own country and the British opposition to a state visit. But how can you hate the Queen? Yes, she's royalty, but has no power. She quiet and gracious and does the job of queening well.
I do believe that we should seriously downsize the royal family. I will not be watching the royal wedding and resent my taxes paying for it. I've seen people claiming that it will increase tourism and bring money into the country, but here in Wales we won't see a penny of it, even if it does increase visitor numbers in an area of England already pretty saturated with tourists. Ideally I would like to see a small royal family who live more modestly whilst most of their palaces and royal residences are opened to the public. That would bring in money. People still flock to Versailles even though the French got rid of their royalty a long long time ago.