And no less centralised because the UK will now be ruled by one bastard government that cannot be trusted, instead of having the other 27 countries of the EU to moderate.
But it
is less centralized because the sovereign unit is smaller. If you do not like the current UK government, work to change it. The smaller the sovereign unit he more impact an individual can have on its policy.
By your way of thinking one world government would be best because then we would have 195 countries to "moderate".