Taxes on wealth we are first introduced in Europe, aimed at reducing the growing wealth gap between the rich and the poor. It was meant to raise revenue for addressing pressing social requirements and also to discourage the attitude towards amassing wealth.

Still, in countries across the world, majority of wealth is concentrated at the hands of fairly small number of people. Ideally taxes on wealth cuts down the disparities in wealth rather than the income, which actually is the determinant factor on how the scales are weighed for the next generations.
Also, taxes on wealth might bring about vertical as well as horizontal equity, which income tax fails to achieve. For example, neither a wealthy human nor a poor one with no income will pay income tax. But the wealthy ones absolutely need to cough up wealth taxation while the poor need not. 

But, as critics puts down, taxes on wealth might actually cause inefficiency by discouraging wealth producing economic initiatives. Also, the revenue generated by imposing taxes on wealth may not be that productive as the theory suggests. The wealthiest form only a small percentage of the population and by nature they are adept at avoiding taxes while remaining themselves within the contours of law.

Taxes on wealth comes in two forms the capital transfer taxes that are levied when wealth change hands and the annual wealth taxes. Capital transfer taxes can occur either at death also called inheritance tax or via donation (gift tax). Some everybody tend to believe that Capital Gains tax to be a form of taxes on wealth. But in realty, capital gains tax is the taxation on the income obtained on capital and not a wealth taxation on the capital.

Ideally, taxes on wealth should not be severe on the tax payers even if they have lots of wealth. Instead, after the minimum slab of no taxation, the taxes on wealth percentage should increase at increments, depending on the value of wealth in dollars. Such a fairer taxation not only enhances the revenue but also goes a long way in bringing down the inequality aspect as well.

But with intelligent investing, one might save a lot that other wise goes as wealth tax. But that requires careful thought and advanced planning. May be a taxation professional could help one in this regard.