Yeah it's reasonable in many cases.
It's a good way of rebalancing an incredibly unequal country instead of waiting for inheritance taxes.
If I was ruling a country in Africa this would be one of my first policies.
Moreover, I do reckon that with the onward march of left populism, there will be hopes of wealth taxes in the future, and they will probably be implemented by the first half of this century in the UK and US, especially at the current trend and pace of wealth flowing up while the plebeians see lifelong stagnation and McJobs on cycles and there being zero policy responses, implemented or suggested, to deal with it.
We're seeing the largest stagnation ever and the recovery is fully going to the top echelon of society.