While I'm a fierce proponent of wealth taxes, efforts like this one will hurt finances of the EU and the middle class more. Only focusing on the EU means the really rich will just move their assets abroad to avoid taxes. Efforts like these need to be enacted on an OECD level and first focus on the $100M+ crowd at a low tax rate. Keeping expectations for massive social impacts low and making sure all loopholes and issues are closed before moving to broader wealth taxes - otherwise the populists will claim failure after a few years (populists backed by rich donors) and call for abandonment of wealth taxes - so they get some peace for the next 50 years.

Equally important we also need to be clever how to implement this tax collection. The ideal setup is a form of sovereign wealth fund, where individuals that need to pay the tax can loan out shares of their company. The issue for lots of very rich people is that they are not liquid enough to fund these taxes. The solution is to allow tax collection by giving these individuals the opportunity to deposit shares of their company as collateral at a wealth fund - giving the fund access to dividend payouts (those need to be tax free) that then cover the required taxation. That way owners of family businesses can keep ownership of their companies and still pay wealth taxes.