What I dislike most about a wealth tax, is that it will become a game of whack-a-mole, as wealth is moved into various assets in an attempt to avoid the tax. Can you take a percentage of fine art? Should I pay to keep that painting, and when and who values it? A simple progressive tax on all income would be great. Pay nothing if you make little, pay a lot if you make a lot, no matter how you make it.
Also, they're probably illegal in the absence of a constitutional amendment, so there's really no point in spending a bunch of effort getting one passed, even if you could solve the problems you cite.
I think the definition of "make" is the practical problem here... "I didn't MAKE that money this year! My stock value just increased!" "I've never had a job! My daddy MADE the money and left it to me! I have no idea how all this works." The rich dodge their increased value in all kinds of ways. As Creedence Clearwater Revival says, "Ooh, the house looks like a rummage sale..." "But when the tax man comes to the door,
"I didn't MAKE that money this year! My stock value just increased!"
Capital gains works. If you sell the stock, you made money and it should be taxed. If it's just an asset you are holding then it shouldn't be taxed year over year. That's just silly.