Big problem... You're comparing two completely different things. The 16% number is based on the fact that most of the wealth earn their income through capital gains which is taxed at a lower rate. So you're comparing income taxes to capital gains taxes. Two completely different items, apple to oranges.
> But it is pretty hard to reasonably come to the conclusion that the rich today are paying similar tax rates to the rich 55 years ago.
You're second point is also wrong. The rich actually pay a higher percentage of the tax burden when rates are cut. Look at the 20's. Taxes were slashed and the percentage of the income taxes paid by the rich doubled. Same today happened with the Bush cuts. The top 10% pay 71% of income taxes, and top 1% around 40%. Here's a chart to show you: http://www.heritage.org/federalbudget/top10-percent-income-e...
How much more exactly should the rich pay?
As for capital gains. You don't want to raise it, unless you're out to punish the rich, since when it's lowered it generates more revenue. When it's increase, it generates less.