You can do more with a two-dimensional spectrum, but I don't agree with the notion that it's necessarily more accurate, certainly not if it splits personal and economic liberty.
Of course there are "2 sides" to liberty and freedom.. Probably more than enough to go to "multi-space" graphs.. And indeed there are many 3 dimensional "freedom" charts as well..
You could not accurately locate Trump for instance on a 1D chart.. He's big govt.. Loves the power. Deficits don't worry him. He's also a populist and quite socially liberal in fact.. It's foolish to even try comparing him to "other Repubs..
And you're NEVER "free" if the government is socially liberal but want to control your every economic choice.. So progressives, populists, libertarians and narco-thug dictators NEED MORE SPACE to visually define them in a single chart.
I won't even discuss 1D charts because my politics is more nuanced than that. And in my head, I'm working in at least THREE axes... Personal Liberty, Economic Liberty, and Foreign Relations..