1) Someone's getting taxed, somewhere. The question is what we want to incentivize.
Working hard for a living? Saving money and investing it to grow the economy? Purchasing food to feed and garments to clothe your family? Trading with people outside the country who make things more efficiently than you can?
Or sitting on underutilized land?
No matter what, someone's ox gets gored. The key is that it should be oriented around good public policy, and that people should have the time to incorporate policy changes into their decision making process.
2) You seem unrealistically worried about government coming in and removing people from houses they own at gunpoint. The actual worst case scenario is someone gets a reverse mortgage from the bank to pay property tax with equity from the home, and they end up bequeathing a smaller proportion of wealth to their heirs when they pass.