I don't really agree with this. Taxes are distortive and doesn't necesarily help inequality. It might even make it worse. But also, there is taxation as a progressive system of government funding, as there is taxation as in "You will never own more than X, because the government will seize it".
In terms of solutions, I'm not a professional economist, but as I read different authors and books, it really seems like we don't understand why we have inequality in the first place. Even Piketty's Capital feels more like explaining that its going on than why. So I'm jitterish about any solution that doesn't help resolve the core cause, for the which there doesn't seem to be consensus
The CEO's pays is a small but funny example about that: CEO's pays increased enormously after by a law thought to dimishing their returns, made their salaries public, and increased CEO's ambition and bargaining power. The very idea to dock their pay increased it.
But those are small bits at the macro-economic level.