*sigh* This same discussion every time.
People who oppose regional pricing refer to the regions that get HIGHER prices than the base (US) one, like the EU and EEA, including the poorer EU countries, sometimes even non-EU Serbia and Montenegro, AU/NZ, sometimes Japan... People who support it refer to the regions that get LOWER prices, like Latin America, former CIS states, China, where not banned Russia (for which massively lower pricing was initially introduced, not because of the purchasing power but to make legal purchases compete with the powerful Russian "piracy" market).
The thing about basing it on country is that you can't make it fair for the people. There are plenty of poor people in wealthier countries that are doubly harmed by it and some wealthy people in poor countries that doubly benefit. And even at country level, it's not fair overall, because it's not actually based on purchasing power, but on marketing and sales. For example most African countries generally don't get regional price cuts because publishers don't expect sales there anyway, so they just don't bother, even though if you'd base it on disposable income they should get the lowest prices.
Still, despite such differences remaining inherently unfair either way they're applied, I wouldn't personally complain if the regional pricing matrix would just have one maximum price that'd apply for all the wealthier countries (US/CA, Western and Northern Europe, AU/NZ, JP, probably South Korea), and either the same price or lower for the rest. But make sure that no non-wealthy country pays more than a wealthy one.