Earned-income (labor) shouldn't be taxed at all. It seems very unjust to tax something that is not a profit, such as a job. We aren't taxed when we trade two pineapples for four pears, so why is trading our time/effort for money any different? It's a scam. Though property taxes are likely a bigger scam. With that we're already in a post-ownership society. You never escape rent, never own anything, which is truly unfair on most of us that have to work to survive and our home is our only real asset. Capital gains should be carrying all of the burden, along with other taxes.
I could be persuaded to agree to a tax system that doesn't distinguish between any forms of income, as long as the first 50K was tax-free for everyone and steep progressive taxation after that, whether it's earned or unearned income. A bar set such as my 50K example to acknowledge that basic food/shelter only requires so much if you're willing to migrate, and everyone is treated the same- including the wealthy. They don't need more than 50K a year either, they're human too.
No matter how it's done (I won't argue details with anyone because that's not my point here)- the tax burden shouldn't be on the working class. It should be on the investment class.
Ultimately we'll likely need more worldwide government to track and tax these individuals fairly to eliminate tax scams like the Caymans. Without that I doubt any policy matters. Step one to that is publicly funding elections so those same people don't control our governments.
The default and only tax-avoidance policy needs to be the same one that applies to the working class. If you don't like taxes, stop making money.