"they were correct across the board"
That's impossible. The "Anti-Federalists" were a diverse set of groups with no unifying themes other than opposition to the newly proposed Constitution. Southern racists and Northern working class movements made anti-federalist arguments for wildly different reasons. It's impossible for anti-federalists to be "correct across the board" because some of the arguments they made were contradictory.
More so, it is trivially easy to find anti-federaist arguments that turned out to be wrong. Several people who identified as anti-federalist predicted that the new constitution would lead to tyranny, and yet, 227 years later, the government retains most of the nominal forms of a liberal polity: a mostly independent judiciary, freedom of media, public criticism, habeus corpus in all but the most extreme cases, etc.