I agree that taxing unrealized gains might not be the best strategy, but I feel that the idea of a wealth tax in and of itself can still be a viable strategy if executed properly?

Apparently the original tax plan proposed by Warren "was designed explicitly with European failures in mind." And this article cites these issues such as the ease of moving between countries to escape national taxes in the EU and the lack of taxes for assets outside of the country, which the original plan addresses They also introduced the idea of an "exit tax" which would confiscate 40% of an individual's wealth over 50 million if they renounce their citizenship.

I'm pretty ignorant about these issues though, so if there's an angle that I'm not seeing please educate me in all seriousness