"Someone might get angry about this tax and do something malicious" is an argument you can make about any kind of tax.

We already have to deal with people squatting domains, and we have laws about trademarks, libel and so on. A tax on valuable domains ought to reduce domain squatting (since it makes it harder to just hold a domain that you're not using, you'd be paying every year) and reduce the market price of domains, which would increase competition and be good for customers. If someone manages to make a viable business out of buying up domains whose owners have been lowballing their value to keep their taxes low, fair play to them, they'll be helping keep everyone honest and keep domains in circulation in the market (but notice that a business like that is only going to be viable if they can sell the domains on to someone who can actually use them pretty quickly, because every year that they're holding them in inventory they're paying the taxes themselves).

> As a society I think we don't want to encourage adversarial pricing on taxes, the same way property tax isn't just based on raw demand (or even linked to it at all depending on the country) and has elements of controls to prevent too much gaming of it.

The current property tax regime is exactly the kind of failure I want to avoid; those "controls" are what leads to all the gaming that locks up our property market and means young people have no hope of ever owning anything. A more raw market-based system would be fairer and more effective.