flat tax?
A flat tax on wealth could be fantastic and solve a lot of things if we could ensure that people couldn't dodge it. (or at least couldn't dodge it any more than they already dodge income)
Some countries already tax their citizens' wealth no matter where it is in the world, no matter what form it's in. If we did that, we could reduce income tax down to nothing and have a far more progressive bracket while encourages the smooth flow of money a lot more seamlessly.