Re: "This measure is expected to impact 170,000 individuals" . . .
If they are intelligent enough to fend for themselves, they will not blink at the prospect of expatriation to a place that doesn't choke them in taxes.
The level of tax that will become due, even with a bad accountant, is nowhere near brain drain levels - it won't even reach permie levels of tax because of expenses being taken before tax and we all know how fungible they are.
That's not to say I agree with the changes, but there will be no brain drain due to this. A few Europeans might go home, but its unlikely - comp here is higher than available in much of Europe and taxes are generally comparable or better here.