I agree with most of that, but using his Secretary as an example when she makes as good a salary as a lot of small business men with 10 or so employees was misleading.
Buffet never proposed a wealth tax but he thought any income over $1,000,000 should be taxed at 30% or some number close to that.
France tried or proposed a wealth tax where you could be taxed on your net worth. Everyone fled to Belgium.
A friend of mine lived in Detroit years ago when they levied a city income tax. He said Detroit was starting to be a $hithole city at that time and anyone with any income fled to the suburbs quickly. He said that was the start of Detroit's decline in his opinion.