Re: Ok but how much tax is fair?
Some of this has already been done. Transfer pricing is more scrutinised and HMRC can challenge vehicles that are purely designed for tax planning that don't have any obvious economic benefit.
But equally some of it can't be done. Companies are supposed to pay tax where their economic activities take place. But that's not always clear. You could argue that all of Facebook's revenue derives from their USA headquarters. The company is the website and all the data they've hoovered up.
Even if you don't accept that extreme view of things, not all advertising (their source of revenue) is done at a national level. And a lot of their costs are at a global level, not a national one. So there's got to be some sort of transfer pricing to account for this, or we're stealing taxes that belong in the US.
There'll never be a perfect answer to this question. And I suspect that international cooperation on it will be very slow indeed.
Thus slowly moving Corporation tax levels lower, and putting it on dividends/capital gains instead seems the pragmatic and achievable thing to do. The lower corp tax rates are, the less incentive to play silly buggers as well.
As for people moving their wealth off-shore to avoid taxes, that's down to what you allow. If someone is solely resident in your country, you can tax them on that overseas income anyway. Or they can subtract the taxes they pay on it abroad from their domestic tax - as now. Hiding assets abroad has beeen getting harder in recent years, even the Swiss banks are less secret than they used to be.